Learn Python - Full Course for Beginners [Tutorial]

in this course I'm gonna teach you everything you need to know to get started programming in python. Python is one of the most popular programming languages out there, and it's by far one of the most sought after for jobs and so if you're trying to get a job or you're trying to you know, automate your life or you try to write awesome scripts to do a bunch of different things than python's for you honestly more and more developers every day are moving their projects over to python because it's such a powerful and the surgeon easy to use language, a lot of programming languages out there just aren't very beginner friendly there's a lot of syntax there's a lot of like little things that if you get wrong the program will yell at you. python is the complete opposite of that. you basically just type out what you want to do in python does it it's that simple there's not a whole lot of syntax to learn the learning curve is literally zero you jump in, you can start writing your first program in seconds. in this course I'm gonna teach you guys. everything you need to know to get started in python. I designed this course especially for python, and each lesson has been specially designed with examples that will help you along the way. with so many people starting to learn python the question isn't, why should you learn pipe on the question is why shouldn't you ? and I think for a lot of people the reason they might not want to learn python is because they're intimidated or they're afraid that it's going to be too hard. trust me I am going to hold your hand through this entire course we're going to talk about all the core concepts in python we're going to look at everything you need to know to start programming in python and start being confidence are writing scripts and start writing programs that are awesome in doing cool things in your life. anyway I'm super pumped to be teaching you guys python. I can't wait to get started in this course and I hope you guys stick around and fall along with the course and learn this amazing programming language in this tutorial dominates three guys how to install python onto your computer. and we're also going to install a text editor that we can use to write our python programs in. so the first order of business is to actually install python on your computer. so we want to do is head over to your web browser and you want to go over here to this page it's just www dot python dot org forward slash downloads and on this page there's going to be two buttons down here and this is going to say download python three point six point three. and at least the version that I have right now or download python two point seven point one four. so here's the thing about python there's actually two major versions of python that are in use currently there is python two and there's python theories you can see over here, this is like two point seven point one four basically any python two version we would just refer to as like python two and here's like the latest python three version. and so there's these two versions that you can download and the first thing we have to decide on which version do we want to download. and here's the basic difference python two is a legacy version of python which basically means that it's like an old version and it's not being like actively maintained or supported like officially by python anymore. python three is like the future of python it's like the newest version it's the one that's getting actively maintained and supported. so there's pros and cons to picking either won a lot of people say like python too has been around longer and so there's more like libraries there's basically just more python code written in python two so therefore like there's a few more things that you can do in pipe onto then you can do in python three but then again python two is not supported and you know, five or ten years from now probably no one's going to be using it. python three it like a site is like the future of python it's the newest version it's the one that you know it's sort of being maintained going forward. so for the purposes of this tutorial I'm going to be teaching you guys python three so we're going to want to download python three now here's vaguely if you learn python three or you learn python to the differences aren't very big. there are a few differences in like some syntax and just so you know little things here and there, but if you learn python three you'll be able to jump right in and code in python two as well don't let anyone tell you that you have to learn one of the other. we're going to learn python three just because it's I think probably the best for a beginner to learn. and so that's the one that we want to download so I'm just going to click download python three and we're gonna go ahead and download this version. and when that's done downloading I'm going to head down to my downloads folder and you'll see here we just have this file doubleclick, and we get this like python installer so I'm going to click through here, and we'll be able to install python three on our computer right when that's done and stalling we can just close out of this and we should begin to get us now we have python three installed on our computer. the next step is we need to choose a text editor so we're going to be writing a bunch of code so we're going to need some you know environment of some program that we can write all that code in. and really you can write python in any text editor you could write it in like a note pad or tax at it, it doesn't really matter but there are special text editors that are designed just for writing python code. and these are called id ease and not stands for integrated development environment. it's basically just a special environment where we can you know ron and execute our python code. and it'll you know basically like tell us how we're doing so were the only if we write something that's wrong or we have errors it'll kind of point us in the right direction of what we need to do to fix that stuff, so in this course we're going to be using an idea and one of my favorites and one of the most popular ity ease for python is called pi charm. so I'm over here on this website. it's called jet brains dotcom forward slash pi charm. and this is the idea that we're gonna be using in this course so I'm just gonna come over here and click this big download now button and we'll go ahead and download this pie charm program right so I'm getting this page are here you can see there's two versions of pi charm one as a professional version and that one's like paid they have to pay for it. but then there's this community version down here and that's free and open source so I'm going to download this one and this should have everything we need to get started using python right when that finishes downloading I'm just going to pull that up in my downloads folder and again we can just sort of run this guy and I'm on a mac so I'm going to have to drag it over to my applications folder. all right so now have pi charm and we have python three installed on your computer. so we're ready to start programming in python. in this tutorial we're going to create our first python program. and we're going to be able to run it and see how everything works. the first thing I want to do is open up pi charm so pi charm was the idea he the integrated development environment that we downloaded in the last tutorial so I'm just going to go out and search for it on my computer and I can just open it up and we first opened up high charm we should basically just get a window prompting us to create a project. so you can see that down here. actually the first thing I want to do though is come over here to configure and I'm just going to click on preferences. and I actually want to change the appearance so I'm gonna go ahead and give this a theme so I just went over here to appearance and behavior appearance and I'm gonna change the theme to darker color because I think it's a little bit easier to use and look at, but you don't have to do that if you don't want you so down here I'm just going to click create new projects and it's going to give us this little window right here so I can just name my project. and I'm just going to name this graph. and then there's other option down here where it says interpreter. now what we wanna select is python version three so if I click down here you'll notice that there's a couple different options. so I'm on a mac computer and by default mac has python version two installed on it. if you're on a windows machine I'm not sure if it does but in this tutorial we're going to be using python three so you wanna make sure that you have python three selected as the interpreter, otherwise you might not be able to fully follow along with what we're doing in this video. so now it's going to come down here and click create. and this is going to go ahead and create our projects for us right so now we have our python project up and running, and I'm sure you guys how we can create our first python program, so over here in this draft folder and this is just that project that we created. I'm just going to right click and I'm saying new and I'm going to come down and click python file so we want to create a new python file this will be our first python program. and I can just give this a name, so why don't we just call this app and it's going to click ok all right so now we have our first python file open and we can just start typing in some python so I want to show you guys. does a very basic python program. and this is just going to be a hello world programs so we're just gonna print something out onto the screen. so when I say what I want to do is I want to type out p r iyer anti prince and wanted to have an open and closed parentheses now inside of those parentheses we can make some quotation marks and inside of the quotation marks I'm just going to tape out hello world. so this is like a very basic python program. and what this is gonna do is it's just going to print out hello world onto the screen. and so now what I can do is I can actually run this file and we're actually getting a little arrow here it wants us to create a new line at the end of the file. and so now in order to run our python program I'm just going to come up here to the top and I'm cinematic run and we'll click this run button right here and I will see what happens so it's asking me what I want to run I can just click add up and down here at the bottom you'll notice that we have this text that just got printed out hello world, so whatever I print or whatever I put inside of this print statement is going to get printed out down below in the council so as long as you're getting that print statements work then you actually written your first python program. and as we go through it forward in the course were can be writing all sorts of awesome python programs. and we're going to do an all sorts of cool stuff in this tutorial I wanna talk to you about writing a basic python programs so we're going to write it as a very simple python program. we're going to look at how we can go ahead and write up programs we're going to talk about how our programs are getting executed by python and we're also going to draw out a little shape onto the screen so this is going to be pretty cool I'm excited to talk you guys about just the bare basics of python, and really just sort of give you an introduction so over here we have our basic text editor and so any of the python code that I write inside of this file is actually going to get executed by a python so this python file has a bunch of python code inside of it. and basically what we're doing when we're programming in python is we're just giving the computer a set of instructions. right that's really what programming is it's just like we're specifying a set of instructions and the computer is going to go off and execute those instructions that we give it. and so the more complex the instructions we give to the computer the more complex the tasks the computer can carry up. so I'll show you guys how we can use some python instructions or some python code in order to draw out a shape onto the screen so I'm actually going to draw out a little triangle. so over here, we can actually print something out onto the screen and python using something called a print statement so I can just type out print. and inside of these parentheses. I can just type some quotation marks and inside the quotation marks we can put whatever we want to print out onto the screen. so I'm gonna copy this and I'm actually going to make a few of these little prince statements and we're going actually draw a sheep. so we're gonna draw like a triangle type shape so down here it's gonna draw a forward slash and then up here I'll make a space and we'll do another foreign sash here will make two spaces with united forward slash. and over here we can make three spaces and afford sash. and now I'm going to draw like a vertical bar is going all the way down. and actually we can do some underscores here as well. I think high school right so now we have our triangle looking shave and you can see it looks kind of like a right triangle so I can save my file. and I can either come up here to run and click run app or of using pie charm you can also just come over here and click this play button and when I click the play button I want you to notice what happens down here so down here we have this little window and this is called the consul and it basically the council is a place where python is going to output some information so when we use this print statement were basically telling python late hey can you print something out onto the consul. so there's a lot of situations where we're gonna wanna see what's going on in our code. and we can use that print statement and print things out to the council. and we can basically like have a little window into what our programs doing in our case we're just going to be printing out this triangle onto the consul. so I'm gonna come over here and click this play button and you'll see down here we're actually printing out that triangle so mission accomplished we were able to print out our shape. so I can really draw any shape I want it as long as I was able to specify inside of these print statements. so essentially what python's doing when I click that play button is it's going into this file and it's looking at all of these instructions in order. so the first thing it does is it goes to this instruction and it says ok, they want me to draw out these like little forward slash in this vertical bar onto the strain, once it does that it goes down to this instruction it says ok they want me to print something on again when it prints dot out it goes down to this instruction etc so python is actually going to execute the lines of code that we write in order. so the order in which I write the instructions matters a lot. so for example if I was to take this last line here and put it up here at the top. now when I save the file. instead of just drawing up that triangle. it's going to draw out this little upside down bottom thing at the top and then the rest of the triangle down here so the order of the instructions actually matters a lot. so this is basically how your python programs are going to go. as we go through this course we're going to learn more and more of these little lines so here we're just using this little print function basically and just print something out on to the screen, there's a bunch of little things like this that we can learn as we go through will learn more and more instructions that we can give to the computer. but in this lesson I just wanted to kind of show you guys the basics right. oh we can essentially just define these little instructions for the computer and the computer will execute them in order. and this tutorial I wanna talk to you guys about using variables in python. now in python and you're going to be dealing with a lot of data and so a lot of times in our program we're going to be working with all types of information and data and values, and sometimes that data can be difficult to manage. so in python we have this thing called a variable. and it's basically just a container where we can store certain data values. and when we use a variable when we put those data values inside containers. it makes it a lot easier for us to work with and manage all of the different data inside of our programs. so variables are extremely helpful and it's sort of like a core topic in python that you're really going to want to know and master. so in this tutorial omelets each you guys. everything you need to know to get started with variables we're going to look at what they are why they're useful and we'll look at the different types of variables and the different types of data that we can store inside of variables, who over here in my python file I just have a very simple program. and it's basically just printing some text out onto the screen. and so this is actually a little story that I wrote it says. there once was a man named george he was seventy years old. he really liked the name george but didn't like being seventy. so this is a valid python program I can go ahead and run this program and you'll see down here in the council everything prints out and it looks great so we have an awesome little python program here. well let's say that inside of our story I wanted to change the character's name so instead of naming the character george let's say I wanted to name the character jon well I'm going to have to go through and I'm going to have to manually change the name george to the name john at every place inside of this story where it's mentioned. so I'm not to go over here and I'll say ok john I'm going to have to manually change that and then ok it's out here we're going up to again manually type in john and change it to john. so in order to change the character's name I had to manually go in and change it in both places. and now let's say ok maybe we want to change the characters ne age also so in addition to changing the name. we also want to change the age let's make him a little bit younger so why don't we say john is going to be thirty five. so you see here I had to come here and manually change the age and then come down here and manually change it again right. and now that we changed it like it's going to work it's going to be updated in our program. but you'll notice that in order to make that change like I had to look through the entire program find it where that value was and change it, and this was only with four lines of the story imagine if I had a story that was like thousands of lines long. and we mentioned that the character's name and age like hundreds of times. we don't have to look through each one of those lines and manually change the character's name and that is not a very good way for us to do this and it's really not a good way for us to manage the data in our program right the character's name in the age. and so we can actually use a variable in order to store the character's name and the characters. age. and when we use that variable it'll make it a lot easier for us to put the character's name and age. inside of our little program here. so I'm gonna show you guys how we can create a variable for the character's name and age. now it's going to go up here above this print statement. and up here I want to create a variable. so when we create a variable in python we actually need to give python a couple pieces of information. the first piece of information we need to give python is the name of the variable so I need to actually assign a name to this container where we're going to be storing information. so all I have to do is just type out the name of the variable that I want to create so I'm going to create a variable called character name. so I'm just going to say character adam's they underscore name so generally when you're creating a name for a variable in python. you want to separate different words with an underscore so I have two words here and I'm separating them with an underscore. and now what I need to do is I need to put a value inside of this very more so basically what I can do is I can just say equals and over here I can type a value so I'm just gonna type out the character's name inside of quotation marks. so we're just gonna type out john. so now we have a variable for the character's name and below this character named variable I want to create another variable called character age certain just going to tape out character underscore age. and I'm going to set this equal to the characters age which is thirty five. so we now have two variables, one representing the character's name and one representing the characters age. so what I can do now as I can replace the character's name inside of this story with this variable. and I'm gonna show you guys how to do that so if we want to put a variable inside of this print statement. I'm actually going to have to do a couple of things. the first thing I'm going to have to do is end off this text in here so I'm going to have to put a quotation marks here the end and you can see I'm basically wrapping this whole thing into a single like quoted line. and now I also have this tax overhear the end so I'm going to have to put a quotation mark here. so now I have a bunch of tax year in quotation marks. and then I also have tax over here in quotation marks now inside of here instead of saying the character's name I want to refer to that character name variable so I'm just going to say plus character underscore name and I want to say another plus sign so I basically I'm saying I want to print out all of this text, plus the value that stored inside of character name plus all of this text. and what this will do is they will actually print out the character's name we print this so I'm gonna go ahead and run this program and you'll see down here and actually let me put a space over here, and we'll run it again. so you can see down here, we still are printing out there once was a man named john. and so what python is doing is when it executes this line of code it's coming over here and it's seeing ok they want to turn out. the value inside of character name so it python's going to go up here it's going to get the value, and it's going to insert it inside of there so I can basically do this for every instance of the character name in my file so I can you know r is copy this guy right here and I can just paste it down here where the characters name is so apace this and you can see now were doing exactly the same thing that we did up there. I can also do this for the characters age someone to come down here and I'll paste in what we just paste it in. and I'm going to change this instead of character name was changed to character age. and I'm going to do this in one more spots are going to do this over here we're mentioning the age and again I'll just change this to carry your age. and so now when I run this program it's going to print out the same story they were printing out before, but now I don't actually have to type in the character's name and the characters age. I can just refer to this variable. and the cool thing about variables as if I wanted to change the character's name. now all I have to do is change it up here so I could change the characters names you like tom or something. and we could also change their age so I could change the age to be like fifty and now that's going to automatically update throughout our entire story when I click this play button you'll see now we're using the name tom and he's fifty years old. so that's where variables can come in handy and this can be a really awesome way to control and manage the data that's inside of our programs with variables you can also modify their values so for example let's say that halfway through the story I wanted to change the character's name why can just make some new lines over here, and down here I can actually assign a new value to one of these variables. so I can say like character underscore name, and in order to give it a different value all I have to do is just say equals and will give it a different value and so let's say halfway through the story we want to change the character's name to mike one now when I run my program you'll see here in the first part of the story it says there once was a man named tom. and in the second part of the story, it's referring to the name as mike. so I actually updated the variable inside of my program over here and that's a really awesome way you know a lot of times in these programs you're going to want to be modifying the values of variables so you can do it just like that. and so finally I want to talk to you guys about the different types of data that we can store inside of these variables. so over here I have the character name and character age and I'm actually storing what are called strings, so a string is basically just plain tax straight so the name tom that's just plain text down here these guys are strings as well. so there's a data type in python, called a string and it's just basically going to store plain text so you know any text that you would have like in a story early know someone's name you can store inside of a string. there's also another type of data that we can store inside of python which is numbers so an additional storing text we can also store numbers. so if I wanted to start a number for example let's say we wanted to store the character age instead of inside of a string. we can store it inside of a number so I could just type out fifty. and when we're storing a number we don't need these quotation marks you only need that quotation mark when you're storing a string so if I wanted to a number I can just write it out like this, and in addition to using whole numbers I can also use decimal numbers. so I could say like fifty point five six seven eight to one three and pythons are going to be able to store that number as well. you can store all different types of numbers and we can also store what's called a boolean value and a boolean value is essentially a true or false value. and there's a lot of instances in programming where we're going to want to represent true or false data for example I can have a variable called like his mail and this would tell me whether or not someone was a male, and in my case it will be true because I'm a guy right so I can actually this needs to be capital so I could sort of value of either true or false. and actually if we were naming this in python we want to use an underscore or so I would say is underscore mail and this can be either true or false so true or false values is maybe not something that you're used to dealing with like in the real world but in programming we're going to be using a true or false values all the time they're super important so like I said there's three basic types of data that we can work with in python there's strings which is just like a plain text, numbers which would be like either decimal numbers or whole numbers like this, and there's true or false values. and these are the basic types of data I mean there's a bunch of other types of data that we can use but I would say ninety nine percent of the time. as a new user in a new programmer to python, you're just going to be dealing with these three types of data so those are the basics of the data and also with variables and you're going to be using variables all the time in python so you definitely want to practice up and get comfortable using them in this tutorial are talks you guys about working with strings in python. now what the most common types of data that we're going to be working with in python is going to be strings and strings are basically just plain text so any text that we want to have inside of our program we can store inside of a string. so I wanna talk to you guys about all the cool things we can do with strings and we're basically just going to get a full introduction into why strings are awesome. so over here, I'm just going to actually print out a strings I'm just going to say print and inside of these parentheses. I can type out a string in order to create a string I need to use quotation marks so I can make an open and close quotation marks just like that now inside the quotation mark I can put whatever text I want the string to have so we could say like draff academy. and so now we have a string with the text draff academy inside of it so if I run my program. now down here we're going to print out draff academy as you can see, and when we have these strings there's actually a bunch of cool things that we can do with them so one thing I could do would be to create a new line inside of the string so if I wanted I could come over here, and I could save backslash n and you can see it got highlighted in a different color. and what this is gonna do is it's actually going to insert a new line into the string so now it's going to say draff on one line and academy on another line. so I'm gonna click play. and you'll see down here we just get draff academy, an addition to the backslash n I could also use a backslash quotation marks so if I wanted to put a quotation mark inside of my string. I can't just put a quotation mark like that because pythons going to think that I'm trying to end this strength. so if I want to include a quotation mark I can just use this special backslash character and that's called the escape character and it basically just tells python that whatever character comes after it we want to render a literally so when I say backslash quotation mark. it basically means like hey python I want to point out a quotation mark. and so now we'll be able to print out a quotation mark right there. I can also use this to print out of backslash so if I needed to put out a backslash. I could see backslash, and it'll just print out a normal backslash now so you can see just like that so if you want and you can use that backslash to make new lines or pronounce quotation marks, or you can just use it as a normal backslash in addition to just typing out a string here I could also create a string variable. so I could come down here up here and we can create a variable and let's call it phrase. and I'm going to set it equal to drop off a colony, so I can store this string value inside of a variable called phrase and then when I want to print out that variable, or I want to access that string variable. I can just type the name of the variable. and you'll see that it's going to print out the value that was stored inside of it. I can also use something called concatenation and concatenation is basically the process of taking a string and appending another string onto it. so I could come over here and I could say phrase, and I can say plus. and now I can add in another string so I could say like is cool. and now this is going to say druff academy is cool, so I'm basically appending another string onto another one they call that concatenation. and so in addition to doing all that stuff we can also use a special thing is called functions and a function is basically just a little block of code that we can run and it will perform a specific operation for us, so we can use functions to modify our strings. we can also use functions to get information about our strings. so I'm gonna show you guys a couple common functions we can use with the strings. and they're actually going to do awesome stuff so in order to access one of these functions I can just say phrase and then I can say dot. and I'm gonna show you guys a function that we can use to convert this string entirely into lowercase so I could just say phrase dot lower. and I'm going to want to type an open and close parentheses, and this will take this phrase, it'll take my string and it will convert it to lower case. so you can see now we just have a draft academy done here but it's entirely in lower case. I could also do the same thing for upper case so I could say phrase dot upper and this will convert the entire string into upper case so you can see now it's entirely upper case. so in addition to converting the string into upper case lower case I can also check to see if a string is entirely upper case are entirely lowercase. so for example I could say phrase dot is upper. and this is going to give me back a true or false value so it's going to be true if the string is entirely upper case or false if it's not. and you can see here we're getting a false value because this is an upper case I can also use these functions in combination with each other so for example, I could say phrase dot upper and that a parentheses and then after this I can say dot is upper and now what it's going to do is it's going to run this upper function, it's going to convert it into upper case. and then it's going to run this is upper function right after that and you'll see now we're going to get a true value back because it will have converted the whole thing into upper case. so you can see now we're getting a true value so the news these functions one after another it can be really useful. and there's a few other ones that I want to show you so we can also figure out the length of this string so if I wanted to figure out how many characters were inside of this string I could just say l e n and I'm actually going to make an open parentheses, and I'm going to make a close parentheses. so I'm essentially saying alien and this is another function it's the length function. and inside of this alien function I'm actually passing this phrase variable basically giving the length function this and it's going to spit out a number so tell me how many characters are inside of this string. as you can see here we get fifteen because there's fifteen characters inside of draff academy. so that's how you can get the whole length of the string and that's going to be really useful as we go forward in python. we can also get individual characters inside of a string so imagine if I wanted to just grab one of these characters like imagine if I wanted to figure out what the first character in the string is we're going to actually use and open a closed square bracket just like that. and in here I can specify the index of the character that I want to graph. so if I wanted to grab the first character in the string I can put in a zero. so if I say phrase square bracket zero, this is going to give me that capital g and you can see down here that's what gets printed out. now I want to point something out in python. when we're working with strings. a string gets indexed starting with zero. so you'll notice that in order to access this g. I had to put a zero in here. that's because in python. when we use indexes on a string we start with zero so if python is counting the characters or its indexing the characters in a string it's going to start with zero so it's going to say g is zero I as one are as to a history. so we would say that g is at position zero in the string. I is at position one r is at position two a's at position three etc. so we start counting at zero. so if I wanted to access the first character in the string. this g I have to say phrase zero and that's just a special thing in python and actually most programming languages do that so they'll start with zero. so for example if I wanted to access this ei, I'm going to have to put zero one two three so I put three inside of here now will be able to access that first a. as you can see we get an a right here, so this is actually really useful being able to grab a specific character inside of a string and you're gonna be using it that a lot as we go forward and python is also another really awesome function that we can use and it's called the index function. and basically what the index function will do is it'll tell us where a specific character or string is located inside of our strings like unsafe phrase dot index. and I can actually give this a value so sometimes when we use these functions in python, we can actually give them information so I can give this of value and we would call this passing a parameter so I would call a value that I would give to a function a parameter and you'll hear that word a lot. so for example I can say inside of here capitol g, and now this is going to return the index of the capitol g inside of our string so it should give us back a zero because g is at the zero of index and you'll see down here that we get a zero because that's where g is. so for example if I put in a inside it here like the lower case a it should give me zero one two three because that's where the first aid is inside of this string, so I can click the play button and you'll see it's giving us a three. you can also put actual words in here so for example I could put like academy in here, or I could even just put like a c a d. and this is going to tell me where this starts inside of my string so when I click play, it's going to give me an a because that's where a cat and he starts right zero one two three four five six seven eight if I put something in here that wasn't in the strings of for example if I put a z in here, that's not in here. it's actually going to throw an error so when I play this you'll see that we get this error down here because the z is not found inside of our program so that the next function again can be really useful we'll be using that a lot. there's also one more than I want to show you which is called replace so we can say phrase not replace and in here I can actually give this two parameters so I can give this replace function two values that it can use. and the first thing I want to you to give it is what I want to replace so for example I could say giraffe. and then I'm going to put a comma in here, and I want to put in here what I want to replace draft with so I could just say like elephant and now instead of saying draff academy this is going to print out elephant academy. so you can see down here it just says elephant academy so this replace function can be really awesome because we can replace certain words or even certain letters inside of our springs with other ones. so those are some basic ways that we can work with strings inside of python and there's a lot of these different functions that we can use with strings. these are some of the most common the ones that I just showed you right now, but if you just do a google search you can find all sorts of python functions that you can try out in use and you know, see what they do, but you definitely want to get comfortable working with strings and python because you're going to be working with them a lot. in this tutorial I wanna talk to you about working with numbers in python and numbers are one most common data types in python and any python program you write is most likely going to be dealing with numbers at some point so I want to talk to you guys about the basics of using numbers we can talk about the different types of numbers that we can represent in python. and I also want to show you guys some awesome functions that we can use with number so we can do a certain like mathematical operations mechanism awesome things with numbers I'm going to show you guys all of that in this video it's gonna be awesome so first thing we can do is we can actually just like print out a number. so if I want to write a number in python it's really easy I basically just write the number so I could say like print too. and this is just going to print the number two out onto the screen, so I can use a whole number like this I could also use a decimal number so I can say like two point oh nine eight seven and pythons are gonna be just fine with that we'll be able to print that on the screen as well. I can also make numbers negative so I could make this two point oh nine eight seven a negative number and python to be able to handle that just fine too. in python we can also use basic arithmetic so I could do things like addition subtraction multiplication fancy like three plus four and now this is going to print this out or was he like three plus four point five. and this will be able to print out the answer so we get seven point five. and we can do a dish in we can do subtraction. we can do division or we could do like multiplication as well so you can pretty much do whatever you want inside of python, and if you want to make more complex mathematical equations we can also use things to specify order of operations so I could use parentheses. so for example if I said three times four plus five what python is gonna do is it's gonna multiply three and four together so it's going to be twelve and then we'll add five to that so we should get seventeen. but let's say that we wanted to change up the order right I could actually put a parentheses around four and five and now it's going to add them first social ad foreign fighters will get nine and will multiply that times three so we should end up with twenty seven, so you can see we can use those parentheses to specify order of operations so I could make like a very complex little equation here and just by using numbers and parentheses. we can also use one other operation which is called the modulates operator so I could say like ted, and use this percent sign three and this is actually read ten mod three and basically what this is gonna do is it's going to take the first number divided by the second number, and it's going to spit out the remainder. so it's basically going to say ok ten divided by three. that's going to be three with a remainder of one. so this is going to give us the remainder. and you'll see down here we get one because that's the remainder of ten divided by three that modulates operator can come in handy quite a bit. we can also store these numbers inside of variables so we can store them inside of these variable containers, so I could come over here and I could create a variable called like my underscored gnome and we'll just store a value of let's say like five and here is why have you come down here and I can just print out my underscore numb. and we'll be able to print that number out to the screen just fine. so in addition to doing things like a basic arithmetic we can also do some other stuff so one thing I could do is I could actually convert this number into a string. so if I wanted to convert this number into a string I can just say s t r and I can put the number that I want to convert inside of these parentheses. and so what's going to happen now is this number is going to be converted into a strings when I click the run button you'll see it's just printing out five but now instead of being a number this is actually a string. and this is going to come in handy when you want to print out numbers alongside strings, so I can come over here and I can say like my favorite number, and we'll be able to print this number along with this string so I click play, and it's as five my favorite number, if I was to get rid of this string right here and I wasn't converting the number into a string. now pythons gonna have a problem with this. it's not going to allow us to do that you can see we get an error so anytime you want to print out a number next to a string you gotta make sure that you use that little string function. so there's a bunch of other stuff that we can do with numbers and a lot of times in python you're gonna want to be using specific metabolic more advanced math operator so there's a bunch of different math functions that we can use on our numbers and a function is basically just like a little collection of code that does something so a function could perform an operation like a mathematical operation on our number, we can also give us information about our number, so I'm sure you guys some of the most common functions that you'll be using in python related to numbers. the first one is called abs and it stands for absolute value so we can get the absolute value of a number. and so over here I'm going to make this variable negative five and basically I can just say abs and I can make an open enclosing parentheses over here, and this is going to give me the absolute value of this number up here, so when I click the play button, you'll see it's just giving us five because five is the absolute value of negative five, I can use a few other functions there is another one which is called pau at so it says p o w and I'm actually not going to use this variable we just as a normal number and this function is going to allow us to pass it to pieces of information so I can give this function two pieces of information. the first is going to be like a number. and the second is going to be the power that I want to take that number two so I could say like three comma two and this is basically just going to be three raised to the power of two, so it's just going to be three squared so we should get nine down here, you can see that we do, so I could pass in like you know some crazy number like we could pass in a four and we can raise it to the power of six, and so we should get like a pretty big number here and you can see we get four thousand ninety six so this power function is really useful for taking numbers to specific powers. so in addition to using this power function we can also use another function which is called max. so I can say max. and what this is gonna do is it's basically gonna return the larger of the two numbers that we pass into it so right now I'm giving this a four and a six and this should tell us which number is higher so over here it's just pulling out six because that's the bigger number. I cannot see is another function called men and this is going to do the opposite so now instead of printing out the max number it's going to print out the smallest number. and it's going to turn out for down here as you can see. another cool function is called the round function and this is going to allow us to round a number so it's just going to follow like standard rounding rules. so if I said like three point to inside of here now is going around it down to just normal three but if I said like three point seven. it's going to round it up to four so that'll allow you to round a number. so there's a few other functions that I want to show you guys but in order to get access to them I'm actually going to have to do something called importing and in python we can actually import external code into our files and so if I want to access these specific math functions. I have to import something called python math so I can just say from up here math import and this star and basically what this is gonna do is it's going to go out and it's going to grab a bunch of different math functions that we can use so I already showed you guys a few of the zipper math functions but there's actually a bunch more. and in order to access them we're going to need to include this line of code inside of our file. so once we have that now I can access a few other so is another function which is called the floor method and it's just f l o r and what this will do is it'll basically just grab the lowest number so it's essentially just going to chop off this decimal point. and you can see over here now we get a three because we're using that floor function. there's also another one called seal. and that's just going to do the exact opposite so that's just going around the number up no matter what so no matter what will always get for which we have a three point whatever here and there's another one which is called square root so it's just asking you our team and essentially this is just going to return the square root of a number so I can say like thirty six. and now we should get six back. so those are also very interesting functions and inside of this math module so we would call this a module and you don't have to worry too much about what that is right now, just know that when we put this line of code into our program it gives us access to a lot more math function so though it basically allows us to do a lot more things with math inside of our program and there's a bunch of different math functions in python and if you why you can basically just go online and search for different math functions. I showed you guys a few here and I would say the ones that we looked at here are probably the most commonly used but there's a bunch more. and like I said you know there's tons of documentation on all this stuff so you can just look up your math functions in python and there's going to be tons and tons like lists of these things that you can use inside of your programs to perform different math operations, but for now that has been a little bit of by using numbers a little bit about doing it on certain math operations and using functions with those numbers in this tutorial I'm going to show you how to get input from the user. so we're basically going to allow a user to input information into our program. and I'm actually going to take the information that the user inputs. I'm gonna store it inside of a variable and then we're going to be able to do something with that variable. so I want to show you guys how we can actually go about getting input from someone. and down here in my python file. all I have to do to get input from someone is I just have to type out input and then an open and closed parentheses. and what this is basically going to do is it's going to tell python like hey we want to get input from a user in python will allow the user to type in some information and inside of these parentheses we can actually type a prompt and so generally when we want the user to enter in some information we want to tell them what we want them to enter. and that's what we can put inside of here so I'm just going to say. enter your name, so we're actually going to create a little python app, which is going to allow the user to enter in their name and then will store the name inside of a variable and then we'll basically just say hi to the user so we'll say like high and then whatever the name they entered was so what I want to do is I actually wanna store whatever the user and put it into our program inside of a variable. so I can actually go over here and I can create a variable I could just call it name and I could set this variable equal to input. so what I'm doing now is I'm taking the value that the user inputs and I'm storing it inside of this variable container called name and so now I have access to whatever they entered it. so what we can do is we can say print and inside of the parentheses I can just print out hello and then I'm just going to add on to this name and actually want to put an exclamation point. so essentially we're getting a name from the user. restoring it inside of the named variable and I'm printing it out onto the screen. so I'm gonna go ahead and play this ? and when we run the program you'll notice down here python is giving us this little problem so it saying enter your name. now in here I can actually type in of values so I could type in might. and then I can just hit enter and pythons going to go ahead and store this value inside of that variable and then it's going to print out hello mike. and so this is kind of cool and actually what we could do is we could prompt the user to enter in more than one piece of information. so I can actually copy this line of code. and I'm an pasted below here and why don't we have the user enter in another variable. so we could have them enter in for example their age. and over here we just want to say enter your age. so now we're able to get two pieces of information from the user. and I could say hello name. and then I can say you are and I'll print out their age so I'm going to print age. so now I'm basically able to get both of these pieces of information from the user I can get their name and I can get their age so when we run this program. I can type in both of those pieces of information so as they enter your name. so we could just make up a name like john and then enter the age that say john is twenty five and now is going to say hello john you are twenty five. so the program is able to get input from the user and then it's able to use that information in order to say hi to the user and tell them how old they are, so getting input from the user is a great way to make your programs more interactive and here we're just scratching the surface right word just basically getting to know a piece of information from the user but you can use these inputs to do awesome things in python and as we go through this course. you're going to see some really cool things that we can do with these inputs in this tutorial I'm going to show you how to build a very basic calculator in python. we're basically going to build a calculator where we'll get to numbers from a user, and then we'll add those numbers together and print the answer out onto the screen. so this will give us some practice in getting input from users and we'll also talk about getting numbers from users as opposed to just strings. so I'm really excited to get started on this calculator. the first thing we want to do is create two variables and inside of those variables we want to store the two numbers that the user wants to add together so down here, I'm just going to say, number one, and that's what we'll call our first variable is equal to. and now I need to get input from the user so I'm going to say. input and inside these parentheses I'm going to say. enter a number, and now I basically want to do the same exact thing but for the second number, so we'll piece this guy down here, and I'm just going to say gnome two and then we'll just say enter another number. so now we're able to store the user's input inside of these two variables. so now all I want to do is just print out the results so I'm actually going to create a variable called result somebody's going to say a result is equal to and basically we just want to add these two numbers together something as a number one plus numb too. and now all we have to do is print out the results I'm just going to print result so we basically have our entire program written out here and this will allow us to enter in two numbers and then we'll add them together and print out the answer so I could play. and down here we can enter our number, so I'm gonna enter the first number we'll say five, and I'm going to enter my second number so let's say eight point zero or else a point three it's now should print out the answer, but if you look over here. that's not quite the answer we were looking for at five plus eight point three is definitely not fifty eight points three and here's what happened when we get input from a user by default. python is just going to convert it into a string, so it doesn't matter what we put down their when we're entering the numbers python's always is going to be like. ok this is a string that's it sounds good right ? it's just going to make it a string in order for us to make these number one and number two variables numbers, we're actually going to have to convert the strings that we get from the user into numbers, and so the way that we can do that is by basically just coming over here and when we add the two numbers together I can use a special python function in order to convert those strings into numbers. and there's actually two python functions that we could use for this. the first is called int so I could say I auntie. I can make an open parentheses and I can make a close parentheses and basically what this is gonna do is it's going to convert whatever is inside of these open or close parentheses into an integer number, and an integer number is basically a whole number so it's like one two three four or five so it's a, it's a whole number another word that can't have a decimal point, so what I could do is I could say I n t, and I could put these inside of parentheses. and now what this is gonna do is it's going to convert both of these numbers into integers in other words into whole numbers that don't have decimals, and it's going to add them together and will print out the result so why don't we do that we'll just see if this works I'm gonna click the play button and down here we'll enter our first number sums can enter into four and then I'll answer in a five and now you can see it's printing out the correct answer four plus five and so that's essentially our basic calculator. but we do have one problem with this calculator salmon run it again and I'll show you guys with that problem is if I wanted to add in a decimal number so we'll add four point three and five point five. you'll see that we're getting this error. and that's because I'm using this ain't function of here and this int function is looking for a whole number. so if I put decimal numbers inside of there it's going to break the programs. there's another function we can use instead of an n we can say float and a float is basically just a number that has decimal so it's a decimal number so I can convert both of these guys into floats and now I'll be able to use decimal number so I can click play. and I can just enter into number so I could say like four and I could also say like five point five. and now it's going to be able to add both of those numbers. even if one of them is a decimal and that's the beauty of using that little float function so in certain circumstances you might want the user to only be able to enter into an integer to a whole number. but in a lot of cases like in this calculator. we want them to be able to answer any number that they want so we're going to use this flow function. so I'm just going to recap what we did one more time we created two variables number one and number two and we basically stored the two numbers that the user's implanted into those variables, then we converted them into numbers and weed out of them together and we printed out the results so this is a pretty cool calculator, i'm happy with it. hopefully you guys learned something. and as we go forward in this python course you're going to learn all sorts of ways that we can make this calculator more complex in this tutorial I wanna show you guys how to build a mad libs game in python, so a mad libs game is basically just a game where you can enter in a bunch of random words so like you know verbs nouns names colors and you basically take all of those words and put them into a story randomly so over here I had my web browser I just have an example of a mad libs so you know down here were basically just taking random words like an adjective or a noun or a pronoun and entering them in sort of a story so like you read through the story than like some random word pops up in mad libs can be pretty fun and I'm sure <?..> yeah he's heard of mad libs before, but if not, now it is a little introduction. so I want to create a mad libs in python and this is going to be really cool so down here I have this, like, a little poem which says: roses are red \ violets are blue \ I love you. and so y'know, this is a compelling classic poem but I think we should mix it up a little bit and create a mad lib for this poem. and so instead of having this red colour over here, I want to have the user answer in their own color instead of having violets, why don't we have them answer in a plural noun. and instead of saying "I love you" why don't we have them say "I love --" and then some celebrity so celebrity. so this is the basic structure for our little madlib. right; it wants you basically have the user answering a color enter in a plural noun. an answer in a celebrity, and I'll take all of those words and put them inside of our madlib and hopefully we end up with something that's pretty funny. so how can we actually go about building this in python well the first thing we're going to have to do is we're going to have to be able to get these words from the user right that's pretty obvious. so I think what we should do as we should create three variables called color plural noun in celebrity and will store the user's inputs. inside of those variables. so up here let's create those variables the first very well I'm going to create is going to be called color so it's a color. and I want to set this equal to the inputs are going to say input and inside of here I was going to give them a prompts all say answer a color. and we can basically just copy this line of code. and I'm going to paste it down below and we'll paste one more time. so now we're going to create our plural noun very also I'll say peoria pluralism now and want to say answer a plural now and actually over here I want a meager coal as well. so then finally we'll create our celebrity variables they enter a celebrity and so now basically we're creating three variables called color plural noun in celebrity and inside of them were storing the color that the user enters the plural noun the user enters and the celebrity these adventures. so the last thing we have to do is replace these guys with those variables so I'm basically just going to add in the colour over here and we're going to add in the plural noun so I can just go like this. and finally what is adding that celebrity. so now we have a prequel mallet and it should be functional everything should work it looks like it's good to go so let's come over here and we'll run our program and then down here in the council. we can play are a little mad libs games so they enter a color I'm just going to say. magenta enter a plural now when we say, microwaves and enter a celebrity you at say Tom Hanks. so when I click enter what should happen is we should get our mad libs printed out some good enter and now we have our methods was as roses are magenta microwaves are blue I love Tom Hanks. so it's a pretty good madlib and obviously you know, the more, the more print statements we put over here you know the better the madlib could be and we could store as many, y'know, variables up here as we wanted. this was just a very simple madlib we only took in three inputs but you know you could see how you could take something like this and create a little mad libs game so your homework for this lesson is to go off and make your own madlib game hopefully one that's a little bit funnier than mine. but that's the basics of creating a mad libs game in python in this tutorial on its artsy guys about working with lists in python. a lot of times when you're programming in python you're going to be dealing with large amounts of data, and when you're dealing with large amounts of data you want to make sure that you can manage it and organize it properly, and the list is essentially just a structure that we can use inside of python to store the lists of information so we can take a bunch of different data values we can put them inside a list and it allows us to organize them and keep track of them a lot easier. so generally you would create a python less than you would put a bunch of related values inside of that list and then you can use it throughout your program so I'm actually eyes are just the basics of using lists we're going to look at some of the common use cases and really just get you up to speed with what lists are and why they're useful so over here in my program I'm actually going to create a list and we create a list a lot might we create a python it's like a normal python variable so the first thing we want to do and we're making a list is give it a name so we want to give it a descriptive name something that's going to basically describe what's inside the list in my case for this example let's make a list of like friends so we could say here's a list of all my friends so I can say friends and I'm going to set this equal to the list of values that represent my friends and we want to create a list we can use these opening closed square brackets. so whenever you use these open and closed square brackets python basically nose okay they want to store a bunch of values inside of this list. so why don't we go ahead and start adding some values so we can say like my friends are like tavern, karen and say jim. so here I have three values inside of my friend's array. so when we're creating a normal variable in python generally we just give it one value right now to create a variable I would give it one value may be a string or a number or a boolean. but when we make lists were able to store multiple values inside of the same like little item inside of the same object right and then what I can do is I can access these individual items inside of my program so inside of this friends list were basically storing all of these different values and that can be really useful so now that we've stored some values let's talk about what you can put inside of a list so you can really put any piece of information in python we could put things like strings, numbers, or booleans so if I wanted instead of just putting strings here I could change like one of these to a number and I could change one of these to a boolean and wouldn't matter python's going to be fine with that. let's change it back to strings just for the sake of the example so now that we've created our list how can we access individual elements inside of this list it's a good question. I'm going to go ahead and print something out to the screen. the first thing we can do is we can just print out the actual list so I can just say print friends and then when I run this program. if we look down here in the console you can see it's just printing out the actual list of friends right, but let's say that I wanted to print out a specific element inside of this list where I can actually refer to elements by their index so each one of the elements inside of this list has a particular index and the index is actually started zero so we would say that this first element in the list kevin has an index of zero, we would say that this other element karen has an index of one. and this third element jim would have an index of two. so even though jim is technically the third element inside of the list. it has an index of two and that's because we start indexing at index position one. and so that is kind of how this work and that's how list indexes work so if I wanted to access a specific element inside of my friends list. I can just referred to it by its index. so over here after which I bought friends I'm just going to tape an open and closed square bracket, and inside this open and close square bracket I want to put the index of the element inside the list that I want to access so fallen to access this guy right here this element. I can just put a zero. so I can say friends zero. and now when I run my program, it's just going to print out that value it's just going to pronounce cabin, if only to access this gem value over here I can put a two and that will give us that jim value you can see right there, so we can access elements based off of their index we can also access elements based off of their index from the back of the list so for example if I said negative one inside of here, this is going to give me access to this value right here for jim. and you can see that's what it does so when we use negatives it starts indexing from the back of the list so if I start at negative two, this is going to give us karen so you can use the negatives to access items at the back of the list. just keep in mind though and this is kind of an interesting we said we would say this first element here is index position zero right but we would say the first element at the back of the list is index position negative one so just keep that in mind. so there's actually other ways that we can access like just portions of this list so for example, let's say I just wanted to select the last two elements in this list and I didn't want us like the first one will in here I can just say one with a colon, and this will grab the element at index position one and all of the elements after that so now we should describe jim and karen or carrying gym in that order. I could also specify a range. so actually let me out in a couple other elements, just so that we can illustrate this better. so are in two more names. so if I wanted to I could select like the element and exposition one up to the element at index position three so it's going to grab this one says one, two and it's actually not going to grab the third one so it's it's going to grab all the elements up to but not including three so it'll grab karen and jim, let's go ahead and run this and you can see it grabs canon japan so you can either just put like one with a colon after it and it'll grab that in exposition in everything after it or even specify like arrange that you want to grab from. so that's how we can access elements inside of this list but we can also a modify elements so for example I could come down here. let's say I want to modify this value right here karen we'll all you have to do is just access that elements I could say friends and karen is that at position of one and I could change this to whatever I want so I could say friends in that position one is equal to mike ? and now when we print out friends and at position one that value is going to be updated so it's just going to say mike instead of saying karen so it can be really useful to modify values inside of arrays so it can be really useful to modify values inside of python lists. so those are kind of the basics of working with lists in python and actually in the next tutorial monastery guys even more ways that we can use these less we're going to learn how to link add elements to a less delete elements from a less copy lists and a bunch of cool stuff with these lists but for now this has just been sort of like the basics of working with lists in this tutorial I wanna talk to you guys about using functions with lists in python, and python a list is one of the most important structures where we can store our information. a list basically allows you to take a bunch of different values and organize them and store them inside of their own little list structure so down here my program you can see I have two less I have a list of lucky numbers. and this is just a bunch of different numbers, and then I have a list of friends so this could be like a list of somebody's friends and it's basically just a bunch of strings with names in them. so these two lists are storing a bunch of different values and what makes this awesome is not only can I store like this many values I mean I could store hundreds or thousands or millions of values. and when you're working with a lot of data and a lot of information and python bees lists are invaluable. so because lists are so important there's actually a bunch of different functions that we can use with lists and those functions allow us to do things like modify the lists and get information about the list so in this tutorial I just want to show you a bunch of those functions we're going to talk about some of the most common and the most popular functions that you would use on lists to make them more powerful and make them more easy to use. so the first thing we can do is obviously just print out a list so down here I'm printing out this friends list when a warm and when I run my program, you see down here we're just printing out all the elements in the list so it's always good to be able to print out all the elements inside of a list, but there's a lot of other functions that we can use so one function is called the extend function in the extend function will basically allow you to take a list and append another list onto the end of it so I could say like friends dot extend and inside of these parentheses I can pass in the list that I wanted to add onto the friends list. so I could say like lucky numbers. and now when I print out this friends list. not only is it going to have all the elements in the friends list it's also going to have all the elements inside the lucky numbers list you can see down here we have all our friends, and we also have the numbers overhears that's a really easy way to essentially just like add two lists together. we can also just add individual elements onto a list so I come down here and I could say friends dot append and this will actually allow me to append another item onto the end of this list, so over here I could just add another name so we could say creed for example and now I'm like adding another friend onto the end of this list so when I run the program. in addition to having the original items that were in the list up here. we also have this additional item at the end and not a pen function is always going to add the item onto the end of the list, but let's say that you wanted to add an item into the middle of the list so like right here right here, there's another list function called insert and insert is going to take two parameters the first parameter is going to be the index where you want to insert the item so why don't we insert it here at index position one. I'm just going to say one and then I'm going to type in the name of the element that I want to add so we can just say like kelly, and now at index position one we're going to have the volume kelly and all of these other values are going to get pushed up they're going to get pushed to the right one index position so now I run the program, you can see we have kavin this new element kelly and then all the other elements have been pushed off to the right, we can also remove elements so for example let's say I wanted to remove this jim value. all I have to do is just a friend's dot remove. and I can just typing whatever element I want to remove so I want to remove this jim element is a now when we run the program jim is going to be gone from the list and we just have these four guys left. you can also remove all of the elements from the list so if I just wanted to completely like reset the less than get rid of everything I could just say friends thought clear. and this is going to give us an empty list so get rid of every single element inside the list. there's also another really cool nothing which is called pop and you can just take out pop like that and basically what pops is gonna do is it's going to pop an item off of this list so when I click the play button, you'll see here that we're left with kevin karen jim and oscar so we basically got rid of the last element inside the list and that's what pop does it pops an element off of the lists of easily removes the last element in the list. so we have our list but let's say that we wanted to figure out if a certain element was in this list right if a certain value is in here so let's say I wanted to check to see if my friend kevin was in this list. why could say friends dot index and in here I can just pass a value so I can say like kevin. and this is going to tell me the index of caverns are the tell me if cabins in the list, so I could play you can see down here it says zero if I was to say like oscar and here for example now would give me the index of oscar. so that's it three but if I put a name that wasn't in here so like if I put mike doth not in the list. and so now we're going to get back an error because it's as mike is not in the list so that's an easy ways you figure out if a specific element inside of the list. and if it is, then you know what index its app, you can also count the number of similar elements in the list so I'm actually going to come down here copy this gem element and will add another jim element into here so I could come down here and I could say friends dot count and will pass in jim and this will tell me how many times the value jim shows up inside of this list. so it should say to which it does down there because we have two values with the text jim and so we have all these values we could also sort this list so I could come over here and I could say friends.sort() and what this will do is it'll sort the list in ascending order so we have a bunch of text here and you'll see what it does. basically what it's going to do is it's gonna put it in alphabetical order are so you see we have j k o and t so the list went from being just random order like whatever we have up here to now it's in alphabetical order. and that's also going to work for lucky numbers so I could say late lucky numbers dot sort and then we'll turn out lucky numbers and they should now be in ascending order, which I'm realizing they already are up here but if I was to take this forty two and put it down here. now it will figure everything out and put it in ascending order anyway. we can also reverse a list so if I wanted I could reverse this not lucky numbers list I could say lucky numbers dot reverse. and now when we printed out instead of being forty to eight fifteen sixteen twenty three. it's going to be twenty three sixteen fifteen eight forty two, so it's basically just reverse the order of the list. and finally there's one more or less functional monetary eyes which is copy. so I can actually create another list. and I could make it as a copy so I could say like friends 2. and we could set this equal to friends dot copy and now friends too is going to have all the same attributes as friends, because it's basically just like copy it basically took a copy of that friends list so you can see it's the same exact thing and copying lists can come in handy in a lot of different situation so those are just some basic list functions and just to kind of like you know get your feet wet in working with lists obviously like the more you work with them the more you practice using these different functions the more comfortable you're going to get. but that's just kind of like a basic overview of what you can do in a sartorial talk to you guys bought tuples in python. now a tupel is a type of data structure which basically means it's a container where we can store different values. now if you're familiar with lists in python a tupel is actually very similar to a list. it's basically a structure where we can store multiple pieces of information, but a tupel has a few key differences from lists that we're going to talk about in this tutorial. first thing I want to do is I want to show you though how to create a tupel. so I can come down here and I can create a tupel and one of the most common examples of tupels his coordinates. so let's say I had a series of like x y coordinates I could create a variable called coordinates and I'm gonna set this equal to an open and close parentheses, and whenever we want to create a tupel inside of python we're going to use these open closed parentheses and inside of here inside these proceeds we're gonna put the values that we want to store so I could for example put a list of numbers, so this could be like my coordinates I could have like four and five. so this would be my tuple with coordinates inside of it. and one of the things about tuples that makes them unique is a tuple is immutable, and you'll hear that word a lot when we're talking about tuples immutable it basically means that the tuple can't be changed or modified. once we create our tuple up here. you cannot modify it cannot change it you can't add elements to it you can't erase elements from it you can't change any of the elements inside the tuple. what you see is what you get once you create the tuple its it does it as it can't change so I can come down here and I can print out some of the attributes inside the tuple. and the way I can access them is just by using an open and closed square bracket. and in here I can pass in a index so troubles are indexed starting at zero so technically we would say that four is at index position one and for -- sorry it is in position zero and five of them is at index position one, so if I said coordinate zero now it should print out four and down here we're printing out four. so if I wanted to print out that five we can just put a one inside of those square brackets and now we'll print out that five so I can access the elements inside of a tuple I can easily access is at each entry. but if I was to come over here and try to change one of the elements so if I said coordinates and coordinate one and I tried to set it equal to something else like ten python's actually going to give us an error when we run this programs often run the program. you see we get this error it says type air tuple object does not support item assignment because it's immutable because we can't change it so that's basically what tuples are how we can create them and you know a couple like I said it's very simple you just created and then you have, um. and now I want to talk to you guys about a common topic in python which is the difference between tuples and lists. so remember a list is basically doing the same thing a list. if one is to create a less we would just use square brackets instead of those parentheses. and if I was using a list I could assign different values to it I could, I could basically mutate any of the elements I could add delete modify change whatever I wanted with the list, but with a tuple. we can't do that and that's sort of the basic difference and really python doesn't say anything more than that it basically just says like one of them's immutable one of them's not but in practical use cases generally people will use tuples for data that's never going to change so you'll steal stored dna inside of a tuple when that data doesn't need to be mutated that's why something like coordinates is such a good candidate for a couple because once you have coordinates like we're probably not going to modify them right, we might add other coordinates. so for example if I wanted I could create a list of tunnels. so I can say like four five six seven, maybe we have some other coordinates like eighty thirty four. so here I have in uh I have a list and inside of it we have these tunnels. but remember these topples can't be modified the values can't be changed so really it's just a case by case basis I would say by a huge majority. you're going to be using lists most of the time. topples or more of a niche you know they're using more special situations. but there are plenty of situations where you want to use tuples so if you're in a situation where you want to store data that can't be changed or mutated then tuples are the way to go to <...> some basics about tuples some basics about the difference between lists and tuples and so a tuple is a great thing to add in c or python repertoire in this tutorial I wanna talk to you guys are by using functions in python. a function is basically just a collection of code, which performs a specific task so I can take a bunch of lines of code that are basically doing one thing I could put them inside of a function. and then when I wanted to do that task or do that one thing that the function was doing, I can just call the function and so functions really help you to organize your code a lot better they allow you to kind of break up your code into different you know little chunks that are doing different things and they're really just awesome so functions are like a very core concept when we're talking about programming in python, so i'll show how to create an awesome function today let's say for the purposes of this tutorial we want to create a function that says "hi" to the user so the one task that our function performs as basically just saying hi to whoever is writing the program so over here, if I want to write a function the first thing I have to use is a keyword in python it's called "def" of d e f and basically when python sees this keyword it's going to say okay this person wants to use a function. so after we type out "def" we need to give this function a name, so just like when we are creating variables we give them descriptive names. we also want to do the same thing with functions. so if I'm creating a function I can just give it a specific name which basically says like what it's doing so we're going to create a function that says hi so I'm just gonna call this function, say hi, just like that. and once we type out the name of the function and so also I could type out say high with no underscore or I could type out say high with an underscore. both are considered like good practices and python and a lot of times if you just have a simple like two word function like this you don't need to put an underscore but we can put an underscore there if we wanted. after we type out the name of the function I'm just going to type into open and closed parentheses. and then I'm going to type a colon and basically what this is doing is it saying to python lake or eye all the code that comes after this line is going to be inside of our function. and in order to write code that's going to end up being inside the function we actually have to indent it sold over here. you'll notice that when I clicked enter my text editor automatically indented attacks so it's automatically like using this indent here and that having one of the rules and python is like the code that goes inside of this function needs to be indented. so if I was to write some code like out here, this is no longer going to be considered inside the function so you can see as I type out code and obviously this isn't real code but as I type text over here that's invented this little like marker over here is basically saying like oh yeah that's inside the function. but then when I write code over here that is like not at the same indentation level as this stuff. it's no longer considering it inside the function so that is a little thing any code inside this function needs to be indented right so our function is just going to say hi to the user so I'm going to have it print out some text it's going to say hello. user. so this is a very simple function obviously we just have one line of code and inside of a function you could have you know as many lines of code as you want but for our purposes we only need one line in order to perform our function. so now all we have to do is call this function so if I want to execute the code inside of this function I have to do something called calling it so if I was to just run my program as it is right now, I'm just gonna run it, you'll see that nothing happens over here right ? even though this function is printing out hello user when I run the program it's not doing it, and that's because of the code inside of a function isn't going to get executed by default. the code inside of a function is only going to get executed when we specify that we want to execute it. and in order to do that we're going to have to do something called calling the function so in order to call a function, you basically just type out the functions name and those open a close parentheses. so I'm just gonna type out say hi and opening close parentheses. and now when we are, when we run this program again, you'll see that it prints out hello user so were executing the code inside of the function. and I want to show you guys just one more thing here just talking to you guys about how these functions actively work so up here I'm going to print top and then down here I'm going to print bottom. so I wanna show you guys the flow of these functions inside the program so when I run this program you'll see we print out top hello user and then bada. so essentially what's happening is when python goes through and executes this program, it goes over here to this first line it says ok we want to print out the word top and then it goes down here and it says ok we want to execute the say high function so python actually jumps up and it goes over this say high function, and it's going to execute all of the code inside of this function so it's going to go through execute all this code. and then once it's done executing all the code and the function, it's going to jump back down here and it's going to move onto the next line which is bottom so that's how like the flow of functions, again with functions generally when we're naming these functions and you want them to be named in all lower case, and usually when we're naming stuff in python if there's two or more words we're going to use an under space or an underscore in between them. so I can write this out as say under score high. but in a lot of situations though if I have a function like this where the name is really short and might just be easier to leave it without an underscore but why we've spent on scoring now just to be a super python official. all right so now we can actually make these functions a little bit more powerful and what we can do is we can give them information. so a lot of times when we write a function we're going to want to have additional information that gets passed in. and these are called parameters so a parameter is a piece of information that we give to the function, so over here I can actually specify that this function needs to receive some parameters so I can basically say like hey if you're gonna call this function, you need to give us some information, you need to give us some parameters and all I have to do to do that has just type out the name of the parameter that I want to receive so why don't we allow the code calling this function to tell it what name to say hi to up here I can just say name and basically what this means is it means whenever I call this say high function we have to give it a name. so down here if I was to call this I have to include a name in here so I can say like mike. and what we can do now is we can actually access this parameter or this variable inside of our function so I could come over here and instead of saying hello user. I could say hello name and basically what this is gonna do is it's just going to say hello to whatever name got passed in here so I'm actually gonna copy this and we will do this twice also hello my kilo steve and now when I run this program you'll see that instead of just saying hello user it saying hello to whichever name I passed in to the function. so that's why this can be really useful right we can give the function information and depending on the information we give it it'll performance task a little bit differently. I could also include more than one parameter so you can I mean technically you could have as many parameters as you want so I can put another one in here would say age. and now I'm going to have to pass in an age along with these, so I'm just going to pass in age and passing an age for down here, and I'm just going to pass in strings, so we can say hello name you are age so I'm passing in two pieces of information. now when we run this program is going to call the function, and it's going to use both of those pieces of information so it's a healthy like you are thirty five hello steve you are seventy. so essentially you were writing out this one line of code which just prints out like hello to someone and were allowing this function to receive two parameter so the name in the age and depending on the name in the age, the function is going to print out hello a little bit differently. that's kind of the beauty of using function so you could pass anything you want into a function so for example, I could pass in a integer. instead of a string for the age. so like I could pass in a number. the only differences over here we're going to have to convert this into a string, but it's going to work. just the same, so you can pass in alm strings numbers bullion's arrays you can really pass any type of data into a function and it's going to work so you can see here we get the same result. so that's the basics of functions and as you go through on with python you're gonna you know being functions more and more, and generally it's a good idea to break your code up into different functions so whenever you have like a grouping of code that's designed to perform a specific task. that's usually a good candidate to be put inside of a function in this tutorial I wanna talk to you guys about using the return statement in python, functions and other python function is basically just a collection of python code that performs a specific task. and when we want to perform that task in our python programs we can call a python function and a lot of times when we're calling a python function we just gonna call it and it does its thing and then we move on with the program. but sometimes when we call a function we're actually going to want to get information back from that function. so when I call the function I want to basically executes task I wanted to execute all the code and then I wanted to like give me some information back so that can be like a particular value. it could be something like telling me how the task went basically the function can just communicate back to us like hey, here's some information. and that's what the return keyword can allow us to do the return keyword can basically allow python two return information from a function. so I'm gonna show you guys how we can do this I want to create a very simple function. and it's just going to cube a number so when we cuba number we take it to the power of three so if I was going to cuba like to be like two raised to the power of three right it's just pretty basic math. so we're gonna make a function that will cuban number and I'll show you guys how we can use that return statement so first thing we want to do is make a function. I'm just going to say death q, we'll call the country the function cube. and over here we can specify any parameters that this function will take. so basically any values that we want to give this function so we're going to give it one function which is just going to be a number so I'm just going to call it numb. and then over here I'm going to type out a colon and then down here, we can put any of the code that we want to be included in this function. so basically this function is just going to keep this number so we could just take out numb times numb times numb right that's going to give us numb cubed. so that's all well and good. and if I come down here I can execute this function so I can basically just call it as a cube. and why don't we pass it a three. so I'm going to go ahead and pass it to three and I'm going to save this. and now let's go ahead and run this code, so we're on the code and you'll see down here. nothing happened right so nothing got printed out in our program facts when we call this cube function it didn't really do anything, so let me try to print this out so immediately prentice function out it'll give us back the information that we want so what about print and will print out the value of the function I'm terrific play we look down here it says none. so when I printed out the value of this function it told me none but really this function is supposed to be q being the number. and here's how we can use the return statement and python I can come over here and I can just say return and now python is going to return whatever value we put over here to the right. so when I call this cube function and I give it a three python's going to go off it's going to execute this function when it sees this return statement it's going to say okay, I want to give a value back to whatever call of this function. and it's going to return this value. now when I print out cube three it should print out the answer because we get an answer back so when I play this you'll see down here, says twenty seven so we got the correct answer. so I can do this with anything wantonly cube like for something as an hour on this and you can see we're constantly getting the correct answer back so that's the basics of using this return statement it allows us to return a value back to the caller in other words back to whatever's calling the function. so I just wanna illustrate this point a little bit further I'm going to go up here I'm actually going to create a variable so I'm gonna create a variable called result and I'm just going to set it equal to cube for this variable result is going to store the value that gets returned from the cube function since it's not in a store like cube for its going to store the value that gets returned from executing that function. so now if I came down here and printed out result. it's actually just going to turn out sixty four again because that's the value that it's storing so this return statement can be really useful for like getting information back from a function, we can use something like a parameter. I guess for as a parameter. we can give information to a function and then we can use the return statement to get information back from a function. and I do I just want to point out one more thing I'm actually not able to put any code. after this return statements so if I came down here and try to put like a prince statement. this actually isn't going to work so this is never going to get printed out so if I just typed out like code right here when we run this program. it's not going to type out code does because when I used this return keyword, it breaks us out of the function so python's going to go through it's going to execute the code in the function whenever it sees this return keyword. it's just going to break back out and we're going to be done so we'll never be able to reach this line of code. so that's the basics of using return statements and you can return any data type you want we could easily return like a string or boolean or an array. it doesn't really matter you can return whatever you want. and a lot of times in a lot of situations you're going to want to get a value back from a function in this tutorial I wanna talk to you guys about using if statements in python. now if statements are a special structure in python where we can actually help our programs to make decisions. so by using an if statement I could execute certain code when certain conditions are true, and I could execute other code when other conditions are true. so basically if statements allow our programs to respond to the input that they are given so depending on the data that we're using in the program are programs will be able to respond so when certain data is certain values we can do certain things and when other data is, other values you can do other things so you know your programs are essentially becoming a lot smarter and actually if statements are things that we as human beings deal with every day so you know as you go throughout your day generally you're dealing with if statements all the time so I want to kind of give you guys a brief introduction into if statements and we'll talk about some of the common if statements that you'd see in everyday life. and now we'll go ahead and do a really awesome example of the kind of like sure yeah what if statements can do for us. so over here in my text editor I just have this little text file and in here I wrote out a bunch of if statements that a lot of people will encounter on a daily basis so here's the first one it says I wake up if I'm hungry. I eat breakfast. so let's break this down a little bit up here it says if I'm hungry. and this is a condition. right this is either going to be true or it's going to be false, right if it's true, I'm going to go ahead and eat breakfast right if it's false under skin to skip whatever was in here and move on, writes that the basics of an if statement. we have a condition in this case if I'm hungry. if the condition is true, then we do the action so we eat breakfast. otherwise we just skip it. so down here we have another one. it says I leave my house. if it's cloudy. I bring an umbrella. otherwise I bring sunglasses. and so this one is a little bit more complex than the one we just looked at you'll see we have our condition right says if it's cloudy. if that conditions true we're going to bring the umbrella. but in this case if the conditions false there is something else that we want to do so in the case of here if this condition was false we just moved on. but now if this conditions false then we're gonna go ahead and bring sunglasses so that's another example of an if statement it's a little bit more complex. finally I have one more down here and this one's even more complex it says I'm at a restaurant. if I want me. I order a steak. so if this conditions true we order the steak, but if this condition is false, then we're going to move on and we're actually going to check another condition. so I'm gonna say otherwise if I want pasta. I order spaghetti and meatballs. this is another condition. if this condition is true we get the spaghetti, if it's not true then finally we're going to move on down here and which is default to ordering the salad so all three of these if statements are valid if statements it's just they get more and more complex as we go down the list so hopefully that's you know kind of wrap your head around what if statements are we're basically specifying conditions. if those conditions are true we're going to do certain things and those conditions are false we can do other things. or we can check other conditions aren't so let's head over to our python file and we'll start writing some actual python. so in here in my app dot python file. I want to create an if statement and I'm going to show you guys a very basic if statement in this tutorial. and then in the next victoria we're going to look at some more advanced if statements. so what I want to do is create a bully invariable. so I'm gonna create a boolean variable that's going to store whether or not the user is a male. so it's just going to be called is underscored mail and I'm gonna set this equal to true because I'm a male. so we have this boolean variable right and right now we haven't set equal to true. I can actually use an if statement to check to see what the value of this variable is and if it's true I can do something so if I want to use an if statement all I have to do is just type up if. and then I just need to type out a condition. so basically I would have to type out like something that's going to be true or false like for example in the other page we are specifying like if I'm hungry or if it's cloudy. here we're just going to check to see if is male. so in other words if the person is male. so remember this has to be a lake it has to be able to be reducible to a true or false value. so in our case where it is using a boolean because that's like the easiest thing we can do. so I said if I specify my true or false condition. now I'm just type a colon. and what I want to do now is make a new line. and so anything that I put below this with an indentation is actually going to be executed when that conditions true so I could put print and down here I can just put you are a male. and now you'll see what happens when I run this program. it's going to go down here and it's going to say you are a male. but if I changed his mail to false so instead of this being true I'd just change it to false. now all of a sudden it's not going to print anything. so it's just going to be blank down here. that's because this condition wasn't true. so anything that I put below this if declaration and that has an indentation like that is going to be executed when the if statement is true. we can also use another keyword in python which is called else and alice is basically going to be like otherwise so you remember, before we said if it's cloudy. I'll bring an umbrella, otherwise I'll bring sunglasses well this is going to be like our otherwise so I can say down here. else and now anything that I've put below else is going to get printed out when that condition isn't sure so long we just put you are not a male. so now we're able to cover both of these situations for this variable. if it's false we can cover that situation. so it says you are not a male. if it's true we can cover that situation as well so it'll say you are a male, so that's pretty cool. but we can also make these more complex and actually before I talk about that you can put as much code as you want inside an if statement so I could have like dozens of lines of code if I wanted. I'm just giving you guys are very simple example so why don't we make this more complex and I'm gonna add another variable into the mix so I'm going to add another you know boolean attribute into this mix. I'm going to make another variable called is tall and we're gonna set this equal to true as well. so now I have two variables in the mix. let's say I wanted to write an if statement that will check both of those variables. so I could write an if statement that's like if their mail and their tall or if they're male and they're not taller if they're not mail in their tall like I can write out a bunch of if statements to check the combination of these variables and so the way I can do that is by using one of two key words so the first keyword I want to show you guys is the or keyword. so I can come over here and I could say if is male or is underscore tall. and what this is basically going to do is it's going to say if the person is either male or if their tall, then we want to do something so this is only going to be true when one of these values is true when one or both of those values is true so down here we can actually put instead of you are a male we could put you are a male or tall or both that's going to be more appropriate. and then down here we would say you are neither male nor tall and that's because if we execute the code inside of this else that means that both of these guys are false rates I'm saying if they're male or their tall, we're going to execute whatever isn't here otherwise that means they're neither male nor tall we're just going to execute this down here so misery as how this works all click play. and these are both true so it's going to say you are a male or tall or both. if I was to set one of these to false so let's set his male eagle false. now, it's still going to say you are a male or tall or both. but if I set them both equal to false. now it's going to say you're neither male nor tall. so that's how the basics of using the or operator. and there's another operator we can use which is called and and basically a similar to or accept both of these conditions have to be true so this is basically saying if the person is male, and they're also tall, then we're going to execute whatever's in here so we could actually change this text to say you are a tall now because we know for a fact that if this is getting executed that are both male and tall. we can also change this print statement down here, this could say you are either not mail or not tall, or both. so you can see it's basically just saying that you're either not one of them or you're not both of them so we could the play button and you'll see because they're both false it's going to say you are either not mail or not tall or both. but if I make them both true, now it's going to say you are a tall male. if I was going to make one of these faster so let's make is tall false. now it's not going to execute this first print statement it's going to execute the one inside of the else, so to say you are either not mail are not tolerable. so that's the basics of and and or and you know you'll be using those a lot of them as you use your if statements, but there's actually one more thing we can do we can add in some more conditions so up here I'm checking if their mail and their tall, but what if I wanted to check if their mail and they're not tall so they're like a short male I can use another keyword in python called else f or really it's just typed out yes I am, and it stands for lcds. and after this we can put another condition so over here I'm going to check to see if their male and they're not tall, so I'm gonna say else if mayor ismail, and now I can type in not tall. and the way I can do that is by saying not an open and close parentheses and saying is tall and basically when I use this not function, it's going to negate whatever is inside of here so if this was true, it's going to make it false and if this was false it's going to make it true. so basically that'll tell us whether or not their tall and that I'm going to use a colon and now down here inside of here were basically just going to type out any of the code that we want to happen when this condition is true so down here we can just print out you are a short male, and there's actually one more condition that we want to check for which would be if they're not mail and their tall, so we can make one more lcs. and I'm actually just gonna copy this guy and we'll paste it down here. so I want to say, if not, is male and his tall, so now we're checking to see if their mail and are either not now and their tall so here we could say you are a you are not a male but are tall. so essentially here we have an if statement that's going to cover every single condition for these two variables so in every single situation of the two values of these variables were going to be able to print something out for it so if I mean both of these true it's basically going to tell us. you are a tall male if I make is male false it's going to tell us. you are not a male butter tall if I made is mailed true and is tall false, then it's going to tell us you are a short male and if I made both of these false it's going to tell us you are either not male or not taller both and actually we need to change this so this should say you are not a male and not tall so that would be a better print out for that situation so you basically see how we can use ifs osoph's and else in order to how I programmed to make decisions and really to respond to the different data in our programs. so unable to respond to every combination of the values for these two variables and that's really cool so in this example we were just using simple boolean variables but in the next tutorial, I'll show you guys how you can actually use something called comparison operators. so we could compare like two numbers or two strings and we could use those as are conditions but for now I think this is a good introduction into if statements. so I'll see you guys in the next tutorial, in this tutorial on a talk to you some more about if statements in python. more specifically we're going to be looking at using comparisons inside of our if statement so if you're following along with the course in the last tutorial, I talked to you guys about just the basics of if statements and we used a couple different boolean variables and depending on the diaries of those bullion's we're able to do certain things in this tutorial we're going to look at another way to use if statements which is with comparison so, instead of just using boolean values we can actually compare different value silly I could compare a couple of numbers like compare couple strings and depending on the results of those comparisons we can do certain things so this is going to be pretty cool and this is really going to give you guys a full understanding of what you can do with if statements so for this tutorial I actually want to create a python function and this function is going to give us the maximum number that we pass into it so this function is going to take three parameters as input, and it's going to print out the biggest number that we give it so let's create this function I was going to say, death. and I'm just going to call it max numb and inside of these parentheses I'm going to specify that I want three parameters as input. someone to say number one, number two and number three. so basically we're passing it three numbers and this function will return. the largest of the three. so in order to figure out which of these numbers is that the largest we're going to have to use an if statement. so I can say if. and over here I need to specify a condition. so I need to put like a true or false value. and so what we can actually do is we can compare these different numbers so I could say if num one is greater than or equal to number two, and number one is greater than or equal to numb three. so basically what I'm doing here is I'm comparing these different number so I'm saying if the first number is greater than or equal to the second number and this is a comparison so when you think about it when we compare these two numbers we're going to end up with a true or false value write num one is either greater than or equal to numb to or it's not it's actually a boolean value rights either true or it's false. same thing over here. the result of this comparison is either true or it's false so technically I'm putting a true or false value in there. I'm just getting that true or false value by using a comparison. and you'll notice over here we're using something called a comparison operator. and basically this is just like how we want to compare them so we're saying like greater than or equal to in this case so down here. if this whole condition is true in other words of the results of these two comparisons end up being true, then we know that none one is the biggest so I can just return num one I can say return no one but we also want to check some other condition so I can say alef and now I want to do some other comparison so I'm going to say, else if none too is greater than or equal to number one and number two is greater than or equal to number three. so I'm doing essentially what I did up here except for none too so again I'm comparing these different numbers and this is gonna end up being a true or false value, depending on the result of the comparison so down here again we can just returned home to because if all this is true that means we're going to end up returning none too. and then finally we can just say else so if num one isn't the biggest and numb to isn't the biggest then we can pretty much assume that number three is the biggest so now we have our function so down here I'm actually just going to call this function, so I'm just going to say, actually I'll print out the results I'll say max numb and will pass in like three four or five so we're basically calling that new function that we just made. and I'm going to go ahead and run this program. so you can see down here in the output we printed out five because that was the biggest. if I was to change this middle onto the biggest so we make the middle on forty now it will be able to take on that situation and finally I can make this like three hundred and it'll be able to handle that so no matter which number numb one number two or number three ends up being the biggest it's able to tell us without a problem. so these comparisons are a really really really common way to make if statements and a lot of times you're gonna want to be comparing different values inside of python, so over here we're comparing numbers. but we could also compare strings so I can easily make these both like you know I can make this like dog and I can make this dog and I could say a different operator so I could say like this double equal sign would mean equal so I can basically say like if this string is equal to that string. you can basically like compare all different data types see nike compare in numbers strings. you can also compare bullion's so once again these are comparison operators and this one is greater than or equal to but there's a bunch of other comparison operators we can use so the most basic is just going to be a double equal sign and not basically checks to see if the two values are equal so it'll say like, if number one is equal to number two, we can also say not equals and this exclamation point will basically mean not equal so it's. if no one is not equal to none too. we also have greater than, less than, greater than or equal to less than or equal to. and those are kind of all of the operators are all the you know the basic comparison operators that are going to be using in python so using comparisons is really awesome and there's going to be tons and tons of situations inside a python where you're going to want to compare different values so these can be extremely useful in this tutorial on how to talk to you guys about building a calculator in python. now having been fallen along with this course you'll know that in the beginning of the course we actually created a very basic calculator. basically the user could just enter into numbers and our calculator would add the numbers together and spit out the answer in this is horrible honorary guys how to build a more advanced calculator so this calculator is going to be able to perform all of the basic arithmetic operations so we can add subtract multiply and divide and were actually allow the user to specify which one of those they want to do, so the user will enter in a number. they'll enter in whatever operator they want to use so plus minus divide mocked by, and then I'll enter in the second number and will perform the operation for them says it can be pretty cool. and it's going to show you how we can use if statements in like a practical application so let's get started. the first thing we want to do is get input from the user so I'm going to create three variables one for the first number one for the second number and one for the operator and will basically store the values that the user inputs into those variables so the first one will just be number one and I'm gonna set this equal to input and we're going to give this a prompts also enter first number and here's actually the thing is whatever the user enters. we're going to want to convert it into a number so generally in python when we get input from the user no matter what they put in it just gets converted into a string. but we don't want a string because we're going to have to be adding or subtracting and multiplying these numbers together ? so whenever they enter in the number I just want to immediately convert it to an actual like number data type instead of a string. so what I can do is I can actually say float. and I can surround this entire input tag with parentheses. and now, what this is gonna do is it's going to immediately convert whatever the user inputs into a float. now that's going to mean that they're going to have to insert a number otherwise we'll get an error but for the most part this should work out for us so I'm actually just going to copy their sky and we'll go ahead and paste it over here, and we'll paste it one more time so we were basically just try to get three pieces of input from the user. so the second thing we want to get is the operator so I'm just gonna say oh p for operator and actually get rid of this flow because we want to keep this as a string. and I'll just say enter operator so it's going to be like. plus minus multiplication whatever. and then finally down here we'll get numb to and again we're going to want to convert this to a float, so I'll say enter second number so now basically what we're doing is we're getting the first number we're getting the operator and we're getting the second number from the user. so what we need to do now is we need to figure out what is inside of this o p. in other words we need to figure out what operator. the user was trying to do so are they trying to do additional they're trying to do a subtraction like we want to figure that out, so we can use an if statement in order to figure that out so I'm gonna come down here and I'm basically just going to create an if statement song and say if. and we want to check a condition so I'm basically going to check to see if this operator is equal to a plus sign so I can say if o p equals plus sign and now if the operator is equal to a plus sign. I'm just going to print out number one plus none too. but let's say that instead of a plus sign they entered in something else so we can say l f o p is equal to. and now we'll check if it's a minus sign. and so here or just print num one minus nothing too. and I actually forgot to put a colon here. so we can just do these for everything so now we can say. lf opie is equal to division and here we'll just divide the two numbers so I can print out number one divided by numb to it, and finally we'll do the same thing for multiplication so I'll say l if opie is equal to astronauts and was print out number one times none too. so basically over here we have every you know condition. but I also want to put in an else statement so in the case that the user enters in an operation. that's not like one of the four that we specified up here I just want to throw an error sums usa opie are actually we just say else and here with this print out lake invalid operator. so this if statement should give us everything we want basically I'm just checking to see if it's equal to a plus sign a minus sign the division sign or a multiplication sign ! depending on which one is equal to we'll do a different operation so let's go ahead and run this and see how we do so I'm going to run this program and it says enter first number let's enter five enter an operator so why don't we just do addition and enter a second numbers do twenty three. so now it prints out the answer twenty eight so our calculator actually works let's try another operator just to make sure. so it would be six and y we multiply it by I don't know five point to three. so now we go off and we do the multiplication and looks like we got our answer so our calculator seems to be working and so basically all we did was we got the input from the user. and then we used if statements to figure out what they wanted to do right so we could check to see if they want an edition we could check to see if they wanted subtraction division and multiplication. and we can also check to see if they entered in an invalid operator so actually why don't we try that too. so enter it in like five and now what does enter unlike an open or close parentheses and four, so you can see here it's able to tell like the program smart enough to know that that's not a valid operator so these if statements can be really powerful and we can use them in combination with getting the user inputs to create a little calculator. in this tutorial on hitachi guys by using dictionaries in python. now a dictionary is a special structure in python which allows us to store information in what are called key value pairs. so essentially I can just create a bunch of these different key value pairs. and then what I want to access a specific piece of information inside of the dictionary. I can just refer to it by its key, so the word dictionary is actually pretty appropriate here if you are familiar with a normal dictionary, you know in a normal dictionary you'd have a word, and then you'd have a definition associated to that word so in this situation the word would be the key. in other words the word is what like uniquely identifies it inside of the dictionary, and then the value would be the actual definition so this is going to make more sense once we start working with this but I just wanted to give you guys a quick introduction. so in this situation I want to create a little program that will allow us to convert a three digit month name into the full month name so I can convert for example like jay a n two january or I could convert an a r into march. like I want to be able to have a program that can do that for us and that's actually a pretty good use case for a dictionary so we're actually going to create a dictionary. and I'm sure you guys how we can do that so, the first thing we need to do in creating a dictionary is just given a name, so I want to give this a specific name so I'm just going to call this month conversions. and now I just want to set this equal to an open and closed curly bracket so whenever we create a dictionary in python. we're always going to wanna created inside of these open and closed curly brackets so inside of the dictionary now we can start defining what are called key value pairs. so I can define a key and that I can give it a corresponding value. and the way that we can do that is by typing out the key and then typing out the value so in our case we're converting three digit month names into the full month names so I would want to type out for example j n and then I can type a colon. and I want to type out the value I want to associate with it so we can say in january. I could basically do this for every combination so I could say like you'd be and this would be february and actually after each one of these we're going to need to put a comma. so I could do the same for march soon say and they are. so essentially what I can do is I can specify an entry inside of this dictionary for each one of these so this over here would be the key in this over here would be the value. and here's one thing is all of these keys have to be unique. so if I was to come down here and change this to j n, this is actually going to give us a little warnings you can see down here it says dictionary contains duplicate keys dots they know no one we're creating dictionary so you'll want to make sure that the keys are unique aren't so I'm gonna go ahead and create one of these for each one of the months and then we'll come back and we'll talk about it. all right so I've gone ahead and created an entry for all twelve of the months so now we have a bunch of unique keys and each one of those keys is associated with a different value. so this is the basics of creating a dictionary is we have a bunch of these different key value pairs. and now what we can actually do is we can access them from inside of this dictionary ? so if I wanted to access a specific key or a specific value. all I have to do is come over here and I'm actually just going to print it out onto the screen so we can see it. all you have to do is referred to the dictionary by name so it's just called month conversions. and there's actually a bunch of different ways that I can access these month names, so I could access different entries inside of this dictionary ? the first way is just by making a open close square bracket inside here I can just type in one of the keys. so for example inside here I could type in and oh thee. and what this should do is it should give us back. the full name for november so when I print this out, you'll see that we get back down here. nov. so I can do the same thing for any of these we can say like an a r. and now we should get marched back so I'm able to refer to the key, and it's going to go into the dictionary and it's going to give me the value that's associated to that qe is actually another way we could do this too so I could say month conversions dot get an inside of here I could also pass in the name of the key so I could pass in like d c and now we'll be printing out december. and what's cool about using this get function is I can actually specify a default value that I want to use. if this keys not found so there's going to be certain cases when we're dealing with dictionaries where you're going to put in a key that might not necessarily map to a value inside of the dictionary you so he put in an invalid key. so let's just try to do that so honest put like aliyu v. that's not a month abbreviation. so when I try to run this, you'll see we get this none down here. and in a lot of cases you're gonna want to create some sort of a default value. so if I'm in this situation where I have a key that's not mappable to any values inside of this dictionary ? I can actually pass it a default value. so inside this dot get function I can make a comma. and I can pass in like a default value to get printed out so I can say like not a valid key. and now when I put in the invalid key instead of saying none. it's going to go ahead and say not a valid key and so this is going to give us like a default value that we can fall back on so these dictionaries are really awesome and the keys over here don't have to be strings so you could also use numbers so for example I can see like zero one tan like I can put any numbers I want over here as keys as long as their unique and that I could access those keys just like I normally would down here with this get function or with those open and closed square brackets so that's sort of the basics of using dictionaries like me really useful to store key value pairs and honestly you're going to be using them a lot in python to store different types of data. in this tutorial I wanna talk to you guys about wild loops in python, and a while loop is basically a structure in python which allows us to loop through and execute a block of code multiple times. so I could specify like a few different lines of code and then I could put that code inside of a while loop and it would basically you loop through that code executing it repeatedly until a certain condition was false. so our lives can be awesome and there's a lot of situations in python where we're going to want to loop through specific lines of code, so in this tutorial I just want to show you guys the healing bare basics of how wildebeests work and then in future tutorial is we're going to use while leaps to create little games and stuff like that so let's talk about wild sum when I create my wild loop. the first thing I want to do actually is create an integer. I'm basically creating a variable that's a number and you don't have to do this for a while but just for our demonstration I'm going to. so I'm going to call this, I am going to set it equal to one. now what I wanna do is I want to create a while loop so I'm basically just going to say. while and over here I want to specify a condition, and this is what's called our loop condition or you can also refer to it as a loop guard and basically we are going to keep looping through the code inside of the while loop. as long as this condition is true. so whatever condition I put in here as long as it's true we're going to keep looping through the code inside the wild is I'm just going to say while I is less than or equal to ten and now I'm gonna put a colon and I'm gonna make a new line. and so anything that's below this while loop declaration and that's indented like this is going to be considered code that's inside the while loop and so that code is going to get repeatedly executed while this condition up here is true. so I'm just gonna put a very simple line of code here where it's going to print out the value of I, and then down here I'm going to actually increment eyes I'm going to add one to eyes I must say I is equal to I plus one, so basically I'm taking this I value and I'm adding one to it is actually a shorthand that we can use in python to do something like this though I could just say I plus equals one and not automatically going to add one to I so this is like a little shorthand and you'll see people in pipe on using that a lot. so over here we basically have our wild lives I have the outline for a while lives we're defining this variable up here and we're going to keep looping through the code inside the while loop. as long as this condition up here is true. so if this condition is false for example if I is equal to eleven, then we're not going to loop through this company more than just going to move on. so down here I'm actually just going to print done with loop. so this was kind of illustrate this for us. so let's go ahead and run this program I'm just gonna run it and you'll see down here we get some output so we're actually going to get numbers printed out one all the way down through ten and then were printing out done with loop so basically what's happening is we're printing out every time we go through this loop so initially I is equal to one right. the first thing that python's going to do when it gets to this while loop is it's going to check this condition. so before it does anything else, it's going to check this condition and it's going to say okay, is one less than or equal to ten. and that's true. so as long as this guy is true we're going to go through and loop through all the code inside of here. so we're going to print out I which has the value of one and then we're going to add one to I so now I'm going to go from one to two. now what we're going to do is we're going to go all the way back up here to this while loop declaration and we're gonna check the condition again. so remember I checked the condition first time and then I looped through all the code, then I'd go back up to the top and I check it again so I'm gonna say ok is I less than or equal to ten at this point I is equal to two so I is less than or equal to tenant. so now we're going to go through and will execute all this code again so I'm going to print out I so it's going to be too and I'm going to add one to eye so now we have three then python's going to go all the way back up to the top and it's going to check the condition again so on every iteration through the loop before python does what's inside of this loop it's going to check that condition. and as long as the condition remains true. we're going to keep executing the code inside the loop eventually though in this program I is going to end up being eleven right so I'm the last iteration it's going to end up being levin, we're going to come back up here, and we're going to say hum is eleven less than or equal to ten nope and so sense it's nope we're going to come down here and we'll print out this done with loop line so that's the basics of how these wildebeests work we're specifying a loop condition. as long as that conditions true will keep executing the code inside of the loop, and after every execution of the loop, we're going to come back up and check the condition again so that's how we end up with this. printing out down here, so that's the basics of a while loop and we can use these volumes to do all sorts of things like wild fruits are very very powerful in this tutorial on a show he eyes how to build a basic guessing game in python, and in this guessing game we're actually going to be using all sorts of cool programming structures that we've learned up to this point in the course. so we're going to be using things like if statements and wild loops and variables and all these cool things in order to build this game so, the basic idea is we will specify lake a secret word. so we'll have a secret word that we store inside of our program and then the user can interact with the program and try to guess the secret word. and so what we want to be able to happen is we want the user to be able to keep guessing what the secret where it is and keep typing in different responses. until they get the secret word right. so that's the basics of what this game is going to be. and now let's go ahead and create it so the first thing we want to do is create a variable to store our secret word. so I can say secret word. and we're just going to set this equal to a secret word so why don't we make it a draft. that's a pretty good secret word. and now what we wanna do is want to create a variable that will store the user's response so I want a variable that will store like all the guesses that the user makes so I'm just gonna call this guess and I'm just going to set it equal to an empty string right now. so now we have a secret word and we have a variable to store the user's guess and what we need to do is we need to be able to prompt the user to input the secret were. but here's the catch. what we want to happen is we want them to enter the secret word. and if they don't guess it correctly we want to prompt them to enter it again. so we can't just use a single input statement we actually have to use something called a while loop. and we can use a while loop in order to continually ask the person to guess the word until they guess it correctly. so let's go ahead and create our while loop so I'm gonna say while and after a while I need to specify a looping condition or a looping guard. basically this is something that as long as it's true we're going to keep looping through this loop. so basically I want to say I want to keep looping as long as the user's gas is not equal to the secret word. so as long as they haven't guessed the secret word. I'm going to keep going through this loop, and inside this loop. what we're going to do is we're going to ask them to input the secret word so I can take this gas variable and I can set it equal to input. and I'm just going to say. enter guess. and so over here we're basically telling the user to enter in their guests. I'm storing whenever they enter inside of this guess variable and then what's going to happen is that we're going to come back up here we're going to check to see if the gas is equal to the secret word if the guests isn't equal to the secret word, then we're going to do it again. but if the guests is equal to the secret word, then we're just going to break out of this loop. and so we can come down here and we can just print out a success message so I could say you win because they got the secret were since they have very very simple program but this is essentially all of the code that we need to be able to build a game like this so let's go ahead and play our game we can run it and see how he did so I'm gonna click play. and down here you can see it's prompting us to enter a guest's so I'm just going to type in some you know random texts we can type in whatever you want. and as long as we're not entering that secret word it's going to keep prompting us to enter different information. but if I enter in the secret word so if I enter in draft. now all of a sudden the programs can terminate and it's going to say, hey you win because we were able to guess the secret word. so that's like a really cool way for us to be able to do this. and we actually have a fully functional guessing game. but I think this guessing game could actually be improved quite a bit. a lot of times when we're making a guessing game we want to set a limit so in other words I want to set a limit for the number of times that the user can try to guess the word. so let's say that the user has three tries right they have three guesses in order to guess the word. and if they can't guess the word after three tries. then they're going to lose the game. but if they can guess the word inside of three tries then they'll win the game right. I think that will be a little bit more of a fun game so why don't we try to program that game, basically we're going to set a limit on the number of guesses that the user can have in order to do this and we're going to have to create a couple more variables down here. in other words we're going to have to store a couple more pieces of information. the first piece of information I want to keep track of is how many times the user has guessed right, so we can just make a variable called guests cao and we'll just set this equal to zero because initially the user won't have guest down in this while loop. every time we go through the loop, I want to increment that gas can write so every time we've gone through this while loop I want to increment that count because that means the user will have guessed so down here I'm going to say. guess count plus equals one and this is just going to add one to the gasket actually whips. so after each iteration of this loop we're going to go ahead and add one to the gas count right so that's the first variable that we're going to need we're also going to want to store another variable and this is going to be called guess limit and basically this is going to tell us how many times the user can guess the words on it it's going to be guests limit and will basically just say three so let's say that the user has three tries to guess the word three strikes and you're out so the user if they can't get it in three tries then we're going to basically say that they lose the game. and I'm also going to need one more variable here, which we're going to call out of gases. and I'm just going to set this equal to false initially. so this out of gases variable is going to be a boolean. and it's gonna tell us whether or not the user is out of gases. so if out of gases is true that means they have no more guesses right they basically lost the game and if out of guesses is false that means that they still have some guesses left so they can keep playing. so let's use these different variables in order to make our program or functional so the first thing I want to do is when I go through this loop. I want to check to make sure that the user has more guesses, right in other words before I let the user enter a gasp. I want to check to see that they haven't already used up all their guesses. so down here I can make an if statement I can say if and inside of the condition I want to check to see that guess count is less then guess limit if gas count is less than guess limit. that means that they haven't guessed the total number of guesses that they have so they have some guesses left. and if that's the case and if that's true, then I'm going to go ahead and give them a guess and then we'll increment the guest count. if this isn't true in other words, if they have reached their guests limit, then I'm going to want to set out of guesses equal to true because there are guesses right they have no more guesses because the gas count wasn't less than the guest limit. and so that means that there are two gases so they have no more gases. so there's actually one more thing we need to do inside of this while loop we need to add another condition onto this loop guard. so right now we're going to keep looping as long as the guest is not equal to the secret word but remember if the users out of gases in other words if they've reached their gas limit we don't want them to guess anymore, right so if they ran out of gas is then we want to basically break out of this loop and not give them anymore guesses so I'm going to go ahead and add another condition onto here and I'm gonna say wow they haven't guessed the secret word and they're not out of gases so it's going to be not out of guesses, then we're going to keep looping so as long as they haven't guessed the word and as long as they still have some guesses laugh we're going to keep looping but otherwise we're going to break out of the loop. and so down here we're printing out you win, but actually when we break out of this loop, there's going to be two possible scenarios. so again, there's two possible ways that this loop could andrei either the gas is equal to the secret word. so either the user guests of the word correctly, or the user ran out of guesses and so there's two situations down here that we need to account for. and so I'm going to use an if statement to figure out which is which I'm going to say if. and we're just going to say, out of gases, and, if the user is out of guesses that I want to print, you lose so we're basically going to be like you lost the game. otherwise though if they're not out of gases. that means that they guessed the word correctly so we're just going to pronounce you win. all right so now we have all the logic for this little guessing game set up and let's see if we can run it and play through it so I'm just going to run this program. and now it's going to tell us to enter a guess so why don't we enter more guesses than we have so we're going to try to lose the game so I'm going to enter one gas two guesses. and now I'm on my final guess so if I don't get it here, we should actually lose the game. and you can see it says out of guesses you lose. so we were able to guess it in the number of trials that we had. let's run the program again and we'll try to win the game. so we'll get a couple wrong. let's say we're on our last gas and unlike okay I can do this so I type in the word and bam we won the game so, that's how we can basically create a game where we have a guess limit so this is a lot of code let me walk you guys through this one more time so you can just get a full understanding of what we're doing up here I created a few different variables we created this secret word variable and we created this guests variable. then we also created some more variable so we created this guests count variable. and this just keeps track of how many times the user has guessed the word. and you can see down here. every time we give them a gas were incremental the guest count. we also have guests limit and gas limit is telling the program how many times the user can guess. so before I go through this while loop the first thing I'm doing is I'm checking to see that the guest count is less than the guests limit. in other words do they still have some guesses left if they do, then we're going to get the input from the user. otherwise, we have this other variable up here called out of gases and out of gases is going to tell us whether or not they have some guesses left. so this is equal to false. that means they have some guesses, if it's equal to true however it means no more dice no more guesses they are done so they lost the game. the last thing we needed to do is specify an additional condition up here. so we are going to keep looping through the code inside of this loop, as long as the conditions up here are true. so as long as they haven't guessed the word. and as long as they're not out of guesses. we are going to keep looping through. and so when eventually the user does break out of this loop, there's going to be two possible situations the first situation is that they ran out of guesses and so we want to check to see if that's the situation. I want to check to see if they're out of guesses. if they are will print out a lose message, if they're not, then they must have guessed it correctly so they win. and so that is how we can use while loops and if statements and also variables in combination with each other to build a pretty awesome guessing game in this tutorial on a talk show guys by using for loops in python. now a for loop is a special type of loop in python which allows us to loop over a different collections of items. so a lot of times will use for loops in python to like loop through different arrays or we can loop over like the letters inside of a string or we could just loop through like a series of numbers so for lives provide a very specific purpose. and the easiest way to kind of wrap your head around why four lives are useful as it is for me to show you guys a bunch of different examples so that's exactly what I'm going to do, we're going to look at why four lives are awesome so down here in my text file and my a python file. I'm going to write out a couple different for lives. so the way that we create a for loop is just by saying four. and now what I want to do is specify a variable and this variable is going to essentially represent a different value every time we go through this for loop and you guys will see how that works in a second but just know that this variable is going to be used on every iteration of our for loop, and each time it will most likely have a different value so in our case I'm just going to call this letter. and I'm going to save four letter inn. and now what I wanna do is I want to specify a collection that I want to loop over. one example of this would be like a string so I can put a string in here I can just put like draft academy. and now I can just put a colon and so basically what this is gonna say it so it's going to say for every letter inside of draft academy. I want to do something and so down here inside of this for loop and again we need to indent this we can put what we want to do with each letter so let me just show you guys like basically what this is going to do so I can print out letters I can print out this letter variable. and it's actually going to print out a different letter inside of this dropoff academy string on every single iteration of this loop. so I'm gonna run this program. and down here inside of my counsel you'll see that I'm basically printing out draff academy so on the first iteration of the loop. I printed out the first letter in draft academy which was g on the second iteration of the loop I printed out I third was our fourth with a. so I'm essentially just looping through all of the letters inside of draff academy. so I'm saying for each letter in dropoff academy. I want to print out that letter. and so this is kind of like how for loops can be used we can define a variable and that variable will change on each iteration of the loop right so on the first iteration of the loop. this letter variable represented a g. on the second iteration of the loop. the letter variable stores the value I excited right so we went through this entire string we were able to print out each letter. so in addition to using this with strings we can also use this with other collections for example like an array. so if I created in array up here, let's call it friends. I'm gonna set this equal to a bunch of different values so we can put like a list of our friends in hearings zelig jim karen and kevin instead of saying the letter why don't we call this friend, and I could say for friend in friends and now will print out the friend so over here I'm saying for each friend inside of this friends array. I want to print out the friend so now we'll actually be able to print out each element inside of that array so not here you'll see we're printing out gym and then on the second iteration were putting out karen and on the third would bring up kevin tso, and he was a loop through all of the values inside of the array. and just so you guys know like you can name this variable whatever you want so I could name I could give this like any random name, and if I want to access it though I have to access it using that same name so we can loop through asking me like an array we can also just loop through a series of numbers so I could say index over here and again this can be anything I'm just gonna call index so we could say for index in range and then in here I can pass in a number so I can pass in like ten for example. and down here I'm just going to print out the index. when I run this program, you guys will see that it's basically going to print out every number in the range from zero to ten, not including ten so starting with zero it's going to put out zero one two three four five six seven eight nine. but notice that it didn't print out ten so it's essentially just printing out all the numbers between zero and ten not including ton. you can also specify a a range of numbers so I can say for example like three and ten. and now this will print out all the numbers between three and ten not including ten so run this program, and you can see we print out three four five six seven eight nine ten not ten so whatever value that you put here in this second position is not gonna get included in the range and ranges can be really is also for example I could use a range to loop through an array just like we did before. so if I wanted I could say something like for index in range and now inside of this range I can pass in the length of the array. so just so you guys know if I wanted to get the length of this array. in other words if I wanted to figure out how many elements were inside of it. I could just type out alli end and then inside parentheses. the name of the array and so this is going to spit out three because there's three elements inside of here right kind of make sense. so what I can do is I can say down here inside of this range function I can just type in eliane and then friends. and so what this is gonna do is it's going to essentially give me a range between zero and the number of friends. inside of this list so down here I could actually type out friends index. and this will allow me to access each individual friend inside of this list. just like we did before but now I'm doing it with a range, so you can see I'm typing out jim care and kevin so actually for each iteration through this loop it's basically going to be printing out friends zero friends one and then friends too because in heater were passing in a three and remember whenever I pass in there it's going to range from zero all the way up to that number but not including that number so that's another way that we can print out all the elements in the array and looping through something like an array is actually a very very common use case for four loops. but like I said we can you spoil hopes to loop through essentially any collection that we have so we can loop through like a string that we could also loop through you know something like an array so this can be really useful and bats are the basics of for loops in python. and I also want to show you guys one more example just while we're here so why don't we go ahead and print out a range up to five brace this would just be a simple program you can use all sorts of logic inside of these four lives. so let's say that I wanted to do something special on the first iteration of the loop. so I could say if index is equal to zero and if the index to zero than we know it's the first iteration of the loop so I could do something special I could like print out first iteration. and then otherwise we could just print lake not first so this would be an example of like maybe you want to do something on the first iteration of the loop and do something else on subsequent iteration so if I play this you'll see only on the first iteration is it printing this out and otherwise it's printing out other stuff so you don't be afraid to put some complex logic inside of these four lives because it can really make your programs more powerful in this tutorial I'll show you guys how to build an exponent function are an exponent function is basically going to allow us to take a certain number and raise it to a specific power. so in python there's actually a really easy way to do this I can come down here and I could print. we could say like too. and we can just do two multiplication signs and I could say three and this is basically just going to be two raised to the third power. so you can see here I can just print this out and we get a cassettes to cube so it's really easy to do exponents in python. but I want to show you guys, how we can use something like a for loop in order to create a function like this of our own sun will actually create an exponent function that will basically do this and we'll use for loops to do it so let's create a function. something as a death and now we need to give this function a name so why don't we call it raise two power and inside of here, I'm going to accept two parameters the first parameter is going to be the base number. and then the second parameter is going to be the power number so we're going to take the base number and raise it to the power number. so over here we can just make a colon now inside of this function when you start writing some code. here's the thing inside the function we don't necessarily know the value of this poem, right for them why have we knew that we were just trying to like square this number or cube this number. I could just return like bass num times basal cell right now it's square the number or I could keep the number bass num so right so this would be like the number cubed. the problem is though we don't know like right off the bat what this value is going to be right this could change like the user can decide that. so in order to write this function we're actually going to need to use a for loop. and I'm sure you guys how it can use a for loop to basically figured this out so the first thing I want to do is create a variable and I'm just going to call it result. and we're just going to set the result equal to one so we're gonna start this off at one. now I want to create a for loop, so I'm basically just gonna say four and over here, I don't want to specify like a index on aug eight index in and now want to specify a range and arrange will basically range us through a collection of numbers. so basically I want to multiply the bass num by itself, as many times as the pound numb specifies right over here I can just make this a range of power numb right and so we'll basically a loop through this for loop as many times as pound them so eponymous two will loop through it twice. economists for will luther at four times and every time through the loop will multiply bass num by itself or actually you'll see we're going to multiply it by this result, and so down here inside this for loop I can basically say result is equal to result times, pacing up this should actually give us everything we need to take this number to the specific power so the actual like result of doing the math is going to get stored inside of this result variable so the first time through the loop, we're just multiplying basin on by one right. and so now result is going to become the same value is based on the second time through the loop so this would be if we were squaring the number. we're basically multiplying resort by basin um again so it's essentially just based on long times based on the third time through the loop we're multiplying result times bass num so we're essentially just like keeping the number so that's essentially what this for loop is doing for us. so the last thing I want to do is right here below this for loop I'm just going to return the result so we'll be able to return whatever the result of raising the number to the power was so let's come down after this function and we're just going to call it so I'm just going to say, actually will print out the answer so save raise to power and the inside of these pregnancies member we can pass two numbers so let's raise three to the second power so we're just going to square three and we'll see how this works so from the program and you can see down here in the console were getting nine. let's try something a little bit crazier drive three to the fourth power and will run this aggregate eighty one so that's three to the fourth power. let's try two to the third power and were getting eight yeah so that makes us so our raised the power function is working just as expected and that is what he has to do it one more time. so inside of this function were taking in two pieces of input were taken in a base number. we're taking it a pow number so that's like the base number is going to be taken to the power number I'm defining a variable here called result and result is where we're going to store the actual result of doing the math. now we specify this for loop, and I'm basically saying that I want to loop through this range of numbers. when I put pounha um here is basically going to range from zero all the way up to but not including the power number silk we'll basically loop through power number of times that makes sense. and then every time through the loop we're just multiplying result by base numb. and then we're just returning results so that's the basics of building a power function and obviously like if you're just trying to take a number to a power in python it's really easy but this kind of shows you like the internal workings right for a function like that to work we would have to actually type something out just like this, and this tutorial I wanna talk to you guys about two different concepts in python. it's going be a pretty cool lesson. first thing I want to show you guys though are two dimensional lists so down here in our python file. I just want to create a basic list so I'm just going to call this number grid. and I'm going to set this equal to a normal let strangers like this now normally if we were creating a list I could just put in a bunch attributes and bunch elements right, and now all of these elements are inside of this number grid lists everybody's happy. but another thing I can do is I can make all of the elements inside of this number grid list lists so the first item in the numbered list is going to be a list. the second item and the number grew less is going to be a list etc. so I'm going to show you guys have to do that I can basically just come down here and why would normally put the first element in the list I can just create another array someone's going to make an open closed square bracket, and now I'm just going to say one two three and I can create the next item in my list I can say four five six, and then let's make another item in this list. I can say seven eight nine and finally we're going to put one more list inside of the number grid list and it's just going to have zero in it so inside of this numbered red lips write this high level overall list, we have four elements in all of those elements are themselves lists. so essentially what we're doing is we're creating a grid right this grid has one two three four rows and one two three carbons right for rose three columns and that's kind of like why these can be useful as we can create a grid like structure inside of python using two dimensional lists. so this is a pretty cool list structure. and I wanna show you guys, how it can access individual elements inside of this list structure so for example let's say I wanted to print out one of these values if they wanted to print out this one right here, the way I can access it is by saying number grid. and the first thing I want to do is make an open and closed square brackets and in here I want to put the index of the row that I want to access. so this would be like row zero because it's the zero of element in the array. this would be row on its it and exposition one this would be row to row three etc so I could put roses grow and now right next to this I'm going to make another square bracket, and I want to put the index of the column so this would be like column one column to column three. so I'm going to put it another zero because this is at the zero index of this first array so I've been zero zero here. now we can print this guy out to the screen and you'll see down here that we get that one so I can also do this for like for this eight for example so this is going to be zero one two can be row two and column one and now we should be able to print out that e. so that's basically how we can access elements inside of this two d list. the next thing I want to show you guys is a nested for loop nested poorly with the situation in mega said well we have a for loop inside of a for loop. and I'll show you how we can use this nested for loop in order to print out all the elements inside of this array so I've basically shown you guys on a parse through a two dimensional list or a two dimensional array. so basically we're going to create a normal for loop so I'm going to say four and I'm just going to say row in number grid. and I'm using the word row here because I'm kind of seeing these guys as rows right these are sort of horizontal rows in our little grid so for each of those rows for each of the elements inside of number grid. I want to loop through so I could actually just print out each row right now and it's going to print out all the rows inside of this list you can see down here we basically just get exactly what we have up there. but I want to be able to access each of these individual attributes inside of each of these array elements so we can actually create another for loop and am I put that for loop inside of here, so now I'm going to say four column in a row. and basically what this is going to give us is each individual column or each individual element inside of these arrays so for example inside of the arrays that are the elements of the number grid over that makes sense so down here. now we can just print out column and this should actually print out every single value inside of this two dimensional array. so let's go ahead and run this program. and down here you'll see that we're basically printing out one all the way down to zero so we're printing out all of the elements inside of all of the arrays inside of the number grid. so that's how we can use two dimensional lists and nested for loops together in both of those things are actually pretty handy in python in this tutorial I'm going to show you how to build a basic translator in python. so essentially we can take in a strings we can take him like a phrase or a word and will be able to translate it into a different language. so over here I have this little file and it basically specifies this language that I made up so I'm calling it the draft language and in the draft language all vowels become g so if I was going to translate an english word into a draft word for example the word dog, I would look through the word dog and any instances where there was a vowel so in our case let's just say a e I o u. I would convert that vowel into a g so dog would map to ddg cat would get mapped into c g t. so those are the basic translation rules. obviously this is a pretty simple language but you get the point any vowel is going to become a g and then we'll get the draft language. so we're going to build a draft translator over here in our python file. let's start making this translator the first thing I'm going to do is just define a translate function. so I'm going to make a function here and I'm just going to call it translate and inside of these parentheses we want this to take one piece of information which is going to be the phrase that we want to translate so I'm gonna say phrase and now inside of this function we need to figure out like ok how can we translate english into our draft language well remember the rules is basically just any vowels become jeez. so the first thing I want to do is create a variable and this variable is going to be the translation so this will be like the final result that we're going to return to the user. so I can say translation for now I'm just going to set it equal to the empty string so this is just going to be like a completely empty string it's not gonna be doing anything. and now what we want to do is we basically want to loop through every letter inside of this phrase. and if it's a vowel we want to change it to g and if it's not avowal we want to leave it alone and we're essentially going to be looping through phrase. and we're going to be adding the letters onto this translation one by one so make sure you guys how we can do this. I'm going to make a for loop somewhere safe for and I'm just going to say a letter in phrase. and so now when I looped through here I can access each individual letter inside of the phrase that they passed in. so what I wanna do is I want to check to see if the letter is a vowel or not right. if it's a vowel than we can add a g onto translation. if it's not available then we can just add on whatever letter it was onto translation anyway so many users if statement I'm going to say if. and there's actually this special thing we can do in python we can check to see if something is in something else so I can say if letter inn. and over here I'm just going to take out all the vowels that was a e I o u. and a e I o to you. I'm basically checking to see if the letter is inside of this string and if the letter is inside of here, then we know that it's a vowel so down here we can handle that case so I can say. translation is equal to translation plus g because if this letter is a vowel we just wanted to convert it into a g. otherwise though I can basically just say translation is equal to translation plus letter. so in the case where we have a vowel I'm adding a g onto translation and the case where we don't have a vowel. I'm just adding on whatever letter it was on to translation so finally down below this for loop we just want to return the translation so I'm just going to say return translation. and now we have a awesome translate function and it should probably work so let's come down here and we'll test it out so we only allow a user to input some information so I'm basically going to call this function. actually we're going to print it out so we'll print this out and I'm going to call this function translate and inside of here I'm actually just gonna pass whatever the user inputs so I can just say input and inside of these parentheses I can say the problem so enter a phrase, and so now I'm basically combining all these statements together I'm saying I want to print out the translation of whatever the user enters in. so let's go ahead and run this program and we'll see how we do so I'm gonna run the program it says enter a phrase actually let me format this a little bit better. okay that's it says enter a phrase. so let's go ahead and do that. so let's just type in the example we use before him and say dog and so now out pops the answer which is d g g. so that's kind of cool. and we can just keep running this as many times as we want so I could type only. to be or not to be, this is like a little bit longer of a string, and you can see it translates it into our draft language. so that's basically how we can create our little a translator out and that's pretty cool. as you can see we're using a for loop in combination with an f loop and that's a really powerful structure and actually there's one place over here where we can make this a little bit more efficient so instead of saying if letter in this string. you'll notice here I'm checking to see if it's in all the lower case and the upper case. I could actually just say if letter dot lower in and now I only have to type out the lower case letters, and it's still going to do the same exact thing so that's a little like hack or whatever that we could use and there's also one more problem with this program so you'll notice down here we're setting the translation equal to the translation plus g. but the problem is if I was to start my word inside of the phrase with a capital vowel so in other words if I said like on, you'll notice that when this gets printed out, it gets printed out as lower case g and so it's not keeping our uppercase syntax and that's kind of a problem so we can actually use another if statement in here and we could check to see if letter dot is upper and if the letter is upper case then we can just set the translation equal to the translation plus a capital g, otherwise, we can just set it equal to the lower case g. it's a now we're able to control both of those situation so let's just test this and see if it works and to rephrase say on. and now we're keeping that capital letter so those are just a couple different ways that we could make this program a little bit better, but the basic concept is we have a for loop and then we have some if loops inside of it, and we're calling this awesome function that can translate a word for us in this tutorial I wanna talk to you guys about comments in python. this is going to be a pretty short tutorial I just want to give you an overview of what comments are and how we can use them in our python programs. so over here in my python program I just have this line here it says print comments are fun. so if I run my program down here inside of the council it's going to print out comments are fun right, so any code that I put over here is going to get executed by python, but there's actually a special line of code that we can write and it's called a comment and a comment is basically a line inside of our python file that's just not going to get rendered by python, so in python sees it as just going to ignore it it's not going to execute its not going to print anything out. it's just gonna kind of ignore it and comments are basically just used for us humans, so a comment is used for like me or another developer to write a little comment a little like plain tax dino comment inside of a file nor retreat of a comment I could use this hashtag symbol. so in click hashtag and now I'm writing a comment. so I can write whatever I wanted in here I could say like this program is cool and you'll notice when I run the program that doesn't show up anywhere. it doesn't matter what I put off at halftime this is just like ignore by python, it's just for me or another developer to come in here and use. so a lot of times you want to write like a little note inside of your python files or maybe you can write yourself a little reminder. or if you want to write a line to lay explain a line of code to for example I can write a comment that would explain this print statement sighted sailing this prints out a string right now anybody looking at my file would be able to read this and they'd be like, oh that's what this does ok cool so comments are useful for leaving little comments in a python file you want to make comments on multiple lines. you can just create a new line and use another hashtag and so that I could type out whatever my next comment was I mean generally if you're gonna put comments on multiple lines you want to just use multiple hash tags plot there's actually another way that you can write out comments so you can use a triple quotation marks so I'm typing out these single quote and I'm typing not three times so you can see here, up here we have this three times we have this three times. so in here I can you know write any comment that I wanted so I can put you know as much taxed up here as I would want. and same thing when I run this program. it's just not going to get rendered so this is another way to make multiple line comments but the link official python like style guides or whatever just recommends that if you're going to put comments on multiple lines you used these hashtags so you know you can really do whatever you want but if you want to be like super python official then use these hashtags comments can also be useful for doing something called commenting out a line of code. a lot of times when you're writing a program, you might have a line of code in there that is maybe like potentially making stuff up. and so what you can do is you can actually comment out that line of code so I can put a comment in front of this line of code. and now when I run my program. the program is going to run, but it's not going to use this line so sometimes if you're trying to see if like a line of code is causing you trouble or if you want to see what your program would be like without a line of code or even like a block of code, you can just commented out. and that way you're not actually deleting the code from your file you're just commenting it out so pythons gonna ignore it, and those are really the two uses for comments as to write little notes right little comments about different things or to comment out code and as you go forward and python I'm sure you'll find uses for comments in this tutorial on a talk to you guys about catching errors in python, and a lot of times when we're writing python programs you'll encounter of an error so different situations could come up and your program might throw an error or it might throw an exception. and a lot of times when these situations happen though completely stop your program from running. and what we can actually do is we can watch out for you know a certain specific errors that are going to pop up in our program and we can actually handle them. so instead of our program just breaking and stop executing, we can actually handle those errors and do things when they occur so I want to show you guys an example of using this down here I'm saying number is equal to its input enter a number, basically what's happening is I'm prompting the user to enter into a number using this input command and then I'm converting whatever they entered into an integer. so as long as they enter in like a valid integer I can convert it into an integer. so I can convert it into like a whole number and I can store it inside of this number variable that I'm just printing it out so let's try to execute this program, I'm going around the program and you'll see down here it says enter a number, so we can enter in like four for example and when I answer in four everything's going to work and it's just going to print out four and everything is right in the world. and actually I'm going to modify this appears it's a little easier to see. but what if we run the program again. so it says okay enter your number. let's say that I break the rules might don't enter a number so it is ignore what the prompts says and I put you know some random text in here, now when I enter this the program's going to throw an error, you see down here it says value error invalid literal for ants base with basten basically paved and answering an integer like you said you would write. we told them to enter in a number they entered in text so it broke the program. and this is a situation that happens a lot so there's a lot of them in situations where something can just go wrong in our program. and up until now we've just kind of accepted it as a reality but if you're writing a real live python program you don't want something like this to trip up your program, you don't want the entire program to break when somebody just forgets to enter in a number right you want to be able to handle all these different situations, and in order to handle them we can use something called a try except block in a try accept blog will basically allow your programs to try out a piece of code, and if everything goes well then we're great like we could try out entering in the number and if the user enters into correct number great, but if they don't enter in the correct number then we can basically like account for that so they entered it in something like a string when they're supposed to render in a number. we could tell them like hey you entered in the wrong thing so I'm sure you guys how we can use these try accept blocks are going to come up here and I'm just going to say try to make a colon. and I want to indent. both of these things. so both of these things are going to be inside of this try block. now I'm going to make a new line I'm going to come down here and I'm just going to tape out except. and I'm also going to put a colon here, and down here I'm just going to print something out so I'll just say like invalid input. so now since I put this code inside of this try block. if the user enters in something wrong it's going to be able to catch it so it'll be able to catch what the user does wrong and print out invalid input onto the stream. so let's go ahead and run our program. and it's just gonna say enter a number. so we're going to ignore that will enter this end and now instead of yelling at us in breaking the program just says hey invalid input. so was able to handle the error they got called it was able to handle the invalid input error basically just told us hey nowhere input. so this is a really powerful thing that we can do in our python programs basically just to protect our programs right if I want to have my program running for long period the time I can't have something as simple as an invalid input trip it up so I can catch that invalid input using these try except blocks. but here's the thing you notice that this little guy down here is getting highlighted. and let's just see what it has to say so it's basically saying two broad exception clause. and this is a message that we're getting because when I just say accept this will catch any error under the sun so anything that can go wrong in my program for the most part this is gonna accept it so let me give you guys an example, let's say I had in my program I was creating a variable right so I'm gonna create a variable called value and I set it equal to ten divided by the zero. now if you know anything about math you'll know that you can't divide a number by zero it's not possible. so the program isn't going to be able to handle this and you'll see that this is going to throw an error for us. so I run the program. it basically says zero division enter division by zero, we're not allowed to do that right. if I took this and I put this down and out of this try block. and I just pasted it in here, it's going to get caught by this exception that we wrote down here so it's going to get caught by that accepts and when I run the program you'll see it says invalid input. but the problem is that we didn't input something that was invalid right we just divided by zero but it wasn't able to handle that. right so it could not divide by zero it through an error. so even though we didn't get an invalid input even though it was because we divided by zero it's still printed this out. and this brings me up to another point is we can actually catch or we can accept specific types of errors. so for example in this case we got a division by zero error in this case we got an invalid input air I we we put something in that was wrong you can convert the value. so I can create two different except blocks to catch two different types of error so down here I can just make a space and I can specify the type of error that I want to catch. so when we divided by zero it was zero division air. so if I just put zero division error in here. now it's going to catch that zero division later so I can say divided by zero. I can also make another accepts I could say accepts and we can catch the other exception that we got so I think it was a value air right now is we put in the wrong type of value inside of that inputs so now we can print out invalid input. so with these two except blocks were basically able to handle both of these situations so for example if this ends up breaking the program this division by zero, then it'll be able to catch that so down here it'll tell us. hey you divided by zero, but if I was to get rid of this line of code, and I just entered in the number wrong so I came down here and I answered in a string set of a number. now it's going to tell us invalid input so we're going to be able to specify what happens when certain things break. so when we get a valid it when we get a value error we can say invalid input. when we get a zero division error we can say divided by zero and depending on what breaks depending on what happens, we can actually do different things, and I want to show you guys one more thing we can do which is we can actually store this error as a variable. so I can say except I can say as and I can type in a name here so a lot of times people will just say like. ye are our and down here I can print out the actual error so I can just print e r r. and so if we end up dividing by zero. so if I say answer is equal to ten divided by zero. we're going to throw this error and it's going to print out what went wrong so now I can run this program and it just says division by zero so it just printed out the error that we got. so that's another useful thing you can do is you can actually print out the specific error that got thrown. now a best practice in python is to use these specific error so you always want to accept and except for a specific error when you don't want to do is just say except and then just accept anything under the sun. it's this too broad and if not in good practice and pythons you wanna be catching specific errors like this in this tutorial on a talk to you guys about reading from external files in python, you know a lot of times in python you're going to want to read from files that are outside of your python file, so you might want to read information from like a text file or a csv file or like an html file. and you can actually use something called the python read command and it will allow you to read a file that is stored outside of your python file so you can use these files to get information or you can parse through different files and do different things. so I'm gonna show you guys the basics of reading files opening files closing files doing all that stuff over here I have this file called employees dot text and it basically just lists out a bunch of different employees like these can be employees in an office or whatever. so it's just listing out all of this information. so let's say that inside of my app dot python file I wanted to read the employees inside of that file. the first thing I have to do is actually open that file from inside python. so I can use a special command called open. so I can say open and then in here I can type in the name of the file that I want to open so this is either going to be a relative path to the file. an absolute path to the file or just the files name if both files in the same directories on my case app dot python and employees dot text are in the same folder within the same directory so I can just type out the name of the file liking to say employees dot text. and I want to put one more thing inside of this open function, and it's going to be the mode that I want to open the file in which you could actually open files in a couple different modes and the first mode is called read so I just put an r here and that's going to stand for a read and this basically means that I only want to read the information inside the file I don't want to modify it I don't want to change it. I just want to read it I just want to see what's in the file and do some stuff without information. another mode is called right so I can type in this w and writing basically means that you can change the file right you can write new information you can change existing information. there's another one called a and a stands for a pen. and it's basically means that you can append information onto the end of the file so you can't modify any of the information in the file. you can't change any information but you can add new information. and there's one more which is r plus and this basically means read and write so this will give you all the power of reading and writing. so in our case, we are just going to be working with regular are so we're going to be reading from the file. now this open function will essentially just open the file so it's going to like golden map file inside of our file system opened it up and it'll allow us to read through it but generally we're going to want to store this opened file inside of a variable so I can create a variable and we can just call it employee file. and I'm just going to set it equal to this open function. so now the open employees dot text file and all the content inside of it is stored inside of this employee file variable. now whenever you open a file you always want to make sure that you close the file as well so just like we have this open command we also have in close function so I can come down here and say. employee file dot clothes. and this is essentially just going to close the file so we're no longer going to be able to access it and generally it's a good idea whenever you're opening up a file and you want to also make sure that your closing the file at some point so generally once you're done reading it and you can just close it. so that's kind of like how we can open and close the file. now let's talk about how we can get information from the far right there's no point having the file that we can't figure out what's in it so there's actually a few different functions that we can use on this employee filed to figure out what's inside of it. and I'm gonna show you guys some of those so I'm just going to make a print statement. and inside this print statement will basically just print out some information about the employee file so the most basic thing we can print out is just the entire contents of the file. but before I do that I want to show you guys how you can check to make sure that a file as readable. so before we do anything else generally is a good idea to make sure that it's possible to read this file. and there's a function inside of python we can use called readable so I'm just going to type out in poorly file dot readable. and this is going to return a boolean value and it's going to tell us whether or not we can read from this file so I'm going to run my program and you'll see down here we get a value of true and that's because we set the file with a read mode so it's in read mode we can read from it. if I was to put a w here so if I put like right now redouble is going to be false because we can no longer read the file we can only write to the file so I'm going to change this back to our so we can just read it. so once you figure out whether or not the file can be read from let's actually read it so there's another function called employee file dot read and this is basically just going to spit out all the information in the files so when I run the program it's just going to spit out all of this information right all the information isn't that was in that file. I can also come down here and we could read an individual line inside this file so I can say employee filed dot read line. and what this is gonna do is it's gonna read an individual line inside of this file so now when I run this program you'll see it's just reading that first line in the file. and this red line function is actually just reading the first line and then it's basically like moving a little cursor onto the next line so if I was to copy this line of code, and then printed again down here I'm saying employee filed out read line. so it's going to read the first line and then when I say it again it's going to read the line after that so this is actually going to end up printing out the first two lines in the file. when I run this program you'll see we print out jim sales men and dwight salesman. so if I was to do this multiple times I could technically print out every line inside of this file. and you can see we can do that and so that can be pretty useful for reading multiple lines in a file but there's actually another function that is better at doing that. we can say instead of employee father read line we can say dot read lines. and what this is gonna do is it's going to take all of the lines inside of our file and put them inside of an array. and so now when I print this out you'll see we have this array down here it says jim sales men that's the first item in the array to white salesman the second item in the array. it's basically taking each line and putting it inside of an array. so if I want to access a specific line I can just refer to it by its index in the array so if I said one. now this is going to give us that do white salesmen line because that is at index position one inside of the array. you can also use this reliance function with a for loop so I could come up here and create a for loop is going to save four and we'll say employee and employee file and then for each employee we just want to print them out so it actually started we have to put employee file dot read lines up here and so now there's a loop through all the employees in this employee filed out read lines array. so we can actually just print out the individual employee and now this will print out all the employees inside of that files is basically printing out each line in the file. and that can be pretty useful. so you can use all of these different functions like read read line read lines readable you know there's a bunch of these different things that we can do to get information from a file. and so there's a lot of cases where you're going to want to be able to parse through information in a file and this is a awesome way to do it so just to recap in whenever you want to open a file and read from it you can just use this open function type in the name of the file and then the mode, which in our case is going to be r. then you can do all sorts of stuff with it and you always want to make sure that you close it when you've done that's just good practice so that's the basics of reading from files and hopefully you guys can use this in some way shape or form in the future. in this tutorial on to talk to you about writing and appending to files in python. so one of the cool things about python is it allows you to work with external files so I could have like an external text file and I could actually like completely read all the information in it I could pass through it use that information to do certain things, but it isn't a reading a file I can also write a file and that's what I want to talk to you guys about today's writing new files and appending onto existing files over here I basically just have some code written out and this essentially just reads information from this employee's dot text file so you can see over here, I am specifying the mode which is r and that stands for read and then down here under his reading all of the contents of the file and spitting it out on the screen. so I'm gonna click the play button over here, and you'll see that if this executes so it's printing out all of the lines of code in our text file so over here I'm in this employee's dot text file and it just has all this information like employees in an office. but let's say that I wanted to add another employee onto here right ? let's say that a new employee joined our company is that we wanted to add them onto this list. well I can come over here to my app dot python file and instead of reading from the file I want to append it to the files I want to say a and appending to the file basically basically means that you're adding some text at the end of the file so wherever the file ends you're just going to add some text onto there. so what we can do is we can actually add another employee into the file. so instead of printing something out I'm actually just going to say. employee file dot right. and when I say employee filed out right I'm going to be able to write something to the end of the file so I can basically does right whatever I want so why don't we add in another employee into our employees dot text file so we can add in another employee why don't we say like toby. and he's going to be in human resources. so now when I run this program. it's going to add toby human resources onto the end of the file somewhere on my program. and you'll see that nothing shows up down here in the council. but if I go over to my employees dot text file. all of a sudden we have a new entry over here it's toby from human resource is right so I was able to append a line onto the end of this file. but here's the thing you need to be careful when you're writing to files because you can actually mess up a file very easily for example I already added toby here into my file. but if I was to run this program again, you'll see that over here in this employee's dot text file it when I hadn't added toby again right so it added this employee here again and also you'll notice that in this case, these employee didn't go onto the next line I accidentally ran my file again and all the sudden it messed up this file over here and so appending you really need to be careful because if you actually go under file again or have you you know, append something on something wrong to the file it's permanently it's getting saved inside of the file. so I want to talk to you guys are a little bit more about you know appending another thing we can do let's say we wanted to add another employee and you'll notice over here in this employees that text file when I appended it on again it got appended to the end of the existing line right so the first time I had a new line there but if you don't have a new line at the end of your file and you all and you want to add a new line, you're going to have to add some special characters so let's add another employee and we'll call her kelly, and let's just say kelley is in customer service so kelly is going to be in customer service. and if I want to add this employee onto the end of the file in a new line I'm going to have to put a new line character in front of it so I can say backslash n and this will upend this entry into the file with a new line so on a new line so now when I run this, you'll see we get kelly from customer service on her own line. so you want to make sure that you're aware of like these special characters that you can use they call them escape characters and you're in time you're audi onto a file you want to make sure that you're adding on exactly where you want to add on. so in addition to appending to a file. I can also just like overwrite a file or I can write an entirely new file. this is as we already have this open instead of appending to the file. why don't we just write a file so I'm going to use this w. and now if I say employee filed out right because I'm using w and I'm not using a, it's actually going to override the entire file and it's only gonna put this inside the file so when I run this and we go over to this employee's dot text file you'll see we only have one line inside of this file now it's just kelley customer service. that's because I was using double you not a when you use w it's just overwriting everything that's in that existing file. you can also use w to create a new file so over here I could say employee file as he could to employees one dot text. and now what's going to happen is when I run this it's going to create another file for me song in a run this and you'll see over here in my file browser. we have this new file employees one dot text so if I open this up. it has exactly the same stuff as in this employees file, but it basically created a new file for us and so a lot of times you're going to want to create a new file, and you can use different extensions to so if I wanted to create like a web page I could say index start each tier mel and I could also add in some each team malcolm here so if you don't understand html don't worry about it but if you do I can put like a paragraph in year another paragraph like this is html basically ht mouth like a webpage. and the point I'm trying to make is that you can write out a webpage inside of python by doing something like this so now when I have played this we get this index style html file. and it has some html inside of it so that's one way that writing to files can be really useful you can overwrite an existing file, you can write a new file and create it, or you can append onto the end of a file and there's tons of applications for writing to files and pythons and great language for working with reading writing doing all itself with files in this tutorial on its altea guys about using modules in python. now a module is essentially just a python file that we can import into our current python file so for example if I wrote a python file that had a bunch of like useful functions are useful variables are you know other things like that. I could take that file I could import it into the file I'm currently working on and I could actually access all of those functions all those variables. all the stuff from that external file inside the file that I'm currently working on so I'm sure you guys how we can use module and then we'll talk about like you know where you can find awesome modules and and really why modules make python and awesome language, so over here in my text editor actually created this file and it's called useful tools dot python and basically this file just has a bunch of sort of like useful tools that I might want to use in one of my progress, she'll see over here I have some variables this one is telling me how many feet are in a mile. this one's telling me how many meters or a kilometer. and then we have this list here which lists out all of the members of the beatles, am I also have a couple different functions down here so I have this get file extension function. and this basically just was you know you give it a file name it'll tell you what the extension is, and then we have this other function down here which simulates rolling the dice so you pass it a number bypass it like a six it would roll a six sided dice a passive nine at roland nine sided dice etc so this is like a pipe on file that I wrote. and it has some useful stuff in it, and honestly there's a lot of stuff in here that I might want to use in the other python files that I work with, so let's say I'm over here at this app dot python file and I'm thinking to myself, ha, I think I could use one of those functions that was inside of that useful tools file actually yeah I need to simulate rolling the dice in my program well instead of having to go over here copy this function and then paste it over here in my program I can actually just import this useful tools file and I'll be able to import all of these functions and all of these variables and attributes. so the way I can do that is by coming up here and I'm just going to go right at the top of my file and I'm just going to say. import. and then I want to type in the name of the file that I want to import it so I was going to say, useful underscore tools and pythons going to be smart enough to know that it should go off and grab all the stuff from this useful tools dot pi file so once I've used that important statement I can actually use all of the functions inside of that useful tools file. so for example I could simulate rolling the dice I could say useful tools. dot, and now I'm actually able to access all of the attributes from inside that file so when I say useful tools dot you'll see down here and my little suggestions menu it's telling me like beetles feet miles get file extension meters and kilometers roll dice. so it's giving me access to all of the stuff that was in that file so over here I could just say like roll dice and we could pass this like a ten will roll a ten sided dice. and now this should actually be able to run that function so will simulate rolling a ten cited diet as you can see we got four and this is a really core concept in python which is importing functionality from external python files and this is like huge in python and this is seriously going to change the way that you create your python files so you'll notice like I didn't have to copy any functions or any variables or anything over into this file and yet I was able to use all this stuff that was inside this useful tools file so that is huge and honestly, it's going to save you a lot of time because you can write something once and then you can import it into your other files. so that's really the basics of using modules mean modules are very simple module as any external python file that you want to use some stuff inside of it. I want to show you guys a place where you can go to find a huge list of modules so I'm going to go over here my web browser. and among this website it's actually like the official python docks and basically all I did to get here was just typing list of python modules and google, and depending on the version of python you're using you're gonna want to make sure that you click the right one. I flicked on the version three one and over here on this page you can see there's just a huge list of python modules, and these are basically modules inside of python that you can just access so essentially there's like all of this awesome code that's already been written for you and so if there's some sort of functionality that you want have inside of your python program, chances are there's a module in here that has that functionalities of all sorts of stuff you can do I mean if you just look through this list like you'll see a huge collection of basically just you know a bunch of either python variables are python functions just you know things that you can use to make your programs better. so here's what I would recommend like head over to this page and to sort of look through a lot of these different module is no see what you can see and honestly like if you click on one of them it'll bring you to a page that talks about like how to use they'll tell you like how to import it and just you know some basics about it and this is sort of like the list that on the official python docs but he's using the python community is huge there's tons of developers who use python. and you can actually find a lot of third party modules so if you just go online and you know look up like python module for doing actual python module for doing why chances are somebody out there has already written a python module to do what you're trying to do so. if you get good at using modules and you get good at you know looking for them in finding them you can actually save yourself a bunch of time because chances are that somebody is already written a module to do you know what you're trying to do are like part of what you're trying to do. so now that we've taken a look at all these different python modules I wanted to kind of dive in a little bit deeper into how we can actually use these things so you'll notice here there's a lot of files right there's a lot of different modules that we apparently have access to in python but the question is where all these files store right when I was over here in my program for example I was using this useful tools dot pie fire like I knew where that was I created that file. I was directly involved in making it and I just imported over here it was pretty easy right ? but what about all of these files right what about all these modules over healy where all of these stored and there's basically two types of models here there's built in modules which means they're just built into the python language so we can't just automatically have access to them. and there's no external modules and a lot of these external modules are just stored in basically the same folder that we installed python on our computer so for example let's look at a couple of these right we have on linking base sixty four bd be been ascii like if I come over here, and you'll see I'm over here in milo file explorer I have my python project which is draft. there's also this other folder over here called external libraries. if I was to click down on this and I come down here you can see it's just the version of python that I'm amusing. there's a folder here called lab and this is a very important folder and this is basically storing all of those external modules so you can see if I scroll down here we have all of these different like modules right so here's that base sixty four hears bd be right. a lot of these external modules are stored inside of this lib folder and like is that there's no external modules there's also a few modules that are just like a built in modules that are not can be stored inside of here and you can actually tell so for example if I was to come over here and click on base sixty four. it tells me where the source code so the source codes in lab forward slash base sixty four. we are able to see that right how is I saw that inside of my lib folder this been ascii though for example if I click on this, you'll notice that this isn't giving me a folder cause this is basically just like built in to python so we don't have to worry about you lucky enough I'll just kind of like it just how it works. so some of these are external some of them are built in. and I want to show you guys are in addition to using these modules races. there's a lot of good stuff here and honestly you could spend. you know for years and years just learning about all these different modules. but a lot of times you're going to want to use modules that other people have written and you know there's a lot of developers who work on python and who write different modules so there's a lot of useful modules either that aren't included in this list right they're not going to be inside of this lib folder by default. and what we can actually do is we can install those external module is as third party modules that don't just come preinstalled with python, and I'm sure you guys haven't do that really quick so the first thing you need to do obviously is find a python module that you wanna installed you can download and I have actually used one in the past. python docs it's an external module that you can use to basically use python to create where documents which is pretty cool as you can like format where documents inside of it so I'm just going to look that up here in google. I'm just gonna type in python docks and here's a thing there's tons of these extra modules you don't have to use python dogs. I'm just giving you guys an example but really it he just look up like useful third party python modules there's going to be lists of hundreds of these things online or in my case though python docs has a website and it basically just has like some installation instructions are gonna come over here and it tells me that I can install python docs using the command pip install python docks. so this brings us to something I want to talk to you guys about which is a pip and pip is essentially a program and actually if you have a newer version of python three it comes preinstalled with python three and you can use pipe to install python modules. it's referred to as a package manager and a package manager basically just allows you to like install manage update and uninstall like different python modules so pip is extremely useful. and in order for us to install python docs we're going to have to use pip somno sure you guys are how we can do that, but what I want to do is open up the command prompt or the terminal on my computer. if you're on a mac you wanna open up your terminal. if you're on a windows computer you want to open up your command prompt I'm using a windows right now, so I'm just going to come down to the search bar and type a and c m d and this command prompts you to come up so I'm gonna click this inside of the command prompt we can actually use pip firstly we want to do is check to make sure that pips install and like I said if you have a newer version of python three pictured calm just pretty installed and it should do some work in here if you don't have a newer version of python three though, you might have to install pip separately and there's tons of instructions online and how to install pip. so I'm just going to check to make sure that I have to type in pip haven hyphen version, and they should spit out the version of pip that I currently have. so as long as we have to pip then we're ready to install an external or third party python module. all I have to do is just say pick install and now I just want to type in the name of the python module so in the case of python docks. it was just python dogs like that. now again you don't have to install python dogs I'm just doing this for this tutorial just going to show you guys how this is going to work. but you know what you want to do is go online and look up some third party external python modules, and generally like I'd say ninety to ninety five percent of the time you're going to be able to just install them using pip. in the off case that you can't install them using pip, chances are they'll be like some detailed installation instructions but out say for the most part any late legitimate python module is going to be able to install using pip. so over here to understand a pip install and add a module name so python hyphen docks and when I click enter this is going to go off and install python dogs for ourselves, we enter and it's going to go off and install everything we need for python docs. so you can see we have successfully installed python docks zero point eight point six, so I'm sure you guys where exactly this god placed so normally when we install a external third party module. it's going to get put inside this limb folder. but it's gonna get put inside of a special folder in here called site packages so slight packages is a special folder and if I open this folder, you'll see now we have this docs folder and we also have this python dark zero point eight point six pi three points sakes thought eg info folder so these two folders are basically included in that module installation so you can see this docs folder has a bunch of different python files and has a bunch of stuff in here that we can use. so if I wanted to use this inside of one of my programs I'm just going to refer to the name of the module so in our case, it's just going to be docks. so I used python docks in order to install it but we're going to use docs if we want to import it so I could come up here and I could say import deal c x. and now I can actually use it so I can just say like docs dot whatever and you can see there's a bunch of different stuff down here. there's like a document, document part image part there's a bunch of stuff that we can use with this and obviously depending on the python module you install there can be different instructions. but you can see it got stored down here in this site packages folder. if I wanted to remove this I could use pick to do it so I could just say tip and install and we could just again saying that a module names of python dogs and people now and install this on our computer. so if I was to go back over to this folder, you'll see that those two that docs folder and then that other folder disappeared so they're no longer here, and I'm actually not going to be able to use this anymore so that's sort of the ins and outs of using modules now again there's tons of these modules and I can be dozens and dozens of python courses covering each one of these modules, you know the built in modules the modules that are included by default and external modules. there's tons of these things out there and really as a python programmer now what you can do is you can go out and play around with these different modules. I showed you the ins and outs of installing them and you can use pip to install all these different modules and you know you can make sure that you have owned by checking the site packages folder or the lips folder but really now it's on you to just come and go out and use these modules and don't shy away from this because modules are a huge part of python you're definitely going to want to include them in your python stack. in this tutorial on a talk to you guys about classes and objects in python classes and objects are extremely useful in python programming and they can help you to make your programs more organized and more powerful. so when we're in python we're dealing with all types of data right and a lot of times when we're writing programs we're going to have to work with different types of data and there's essentially like a few basic types of data we can deal with usually things like string cilic plain tax numbers and boolean values those three are kind of like the main types of data that you're going to be working with in python and we have all sorts of structures we can use to store that data you know things like lists or dictionaries. but here's the problem is that not all information not all data not all things can be represented using strings numbers or bullion's right, there's a lot of things in the real world that we can't represent in automating a string or an array, or just a number right in other words something like think of like something like a phone or a computer or a person right you can't really represent those things in like a string or a number you know it in other words like the data types that we have available to us in python can't cover that. and so what we can do with classes and objects is we can essentially create our own data types. so I can create my own data type for anything I want python so I could create like a phone data type and it could represent a phone so I could store all the information I would ever want to know about my phone inside of that data type in and python we could create a class for it and essentially what a classes is just saying hey here's another data type that we want to use in python. so with a class you can essentially define your own data type and its super awesome and classes are extremely useful causes are used in almost every single major programming language out there so in this tutorial I just want to give you guys a basic introduction of classes and using them inside of python so let's say that I'm writing a program, and I want to represent a student inside of this program so maybe I'm writing a program for like a college or a university. let's say that in this program I want to model a student like I want a model a real world objects and I wanted to be a student right where we don't have a student data type and I can't really represent a student in just a single string or a number. so I can actually do is I can create a class for a student and I'm basically creating like a student data type. so I'm sure you guys how we can do that and create our student class it's over here. I'm just gonna make a new file. wouldn't we get a new pipeline vase I'm just going to call it student dot pie and inside of this student dot pi file I want to create a student class. so the way that I can do that is just by typing class. and now I'm gonna type the name of the class that I want to create. so in our case we are going to create a class called student so I'm just gonna say student. and now we're going to make a colon now everything that goes inside of here is going to be inside of our student class so everything that's invented like this will be considered a part of our student class and basically what we can do inside of this student class is we can define a bunch of attributes about a student. so essentially what I'm doing is unlike modelling a student I'm creating our student data type. and I can use things like strings, integers and bullion's in order to map out what a student should be in what a student should have. so I want to create something called an initialize function. and the way I do that as just by typing out a d e f and I was going to take two underscores, and then the word I am I t and then two more underscores, and you also want to type out open close parentheses and inside of those parentheses we want to type out self, and I'm on a colon after that. what I can do inside of this initialize function as I can basically map out what attributes a student should have so we can essentially define like hey, here's the student data type in python so what I want to do is add in certain attributes after this self so I'm just gonna say self a comma. and now we can start thinking about you know what values will represent a student inside of our python programs so if I'm thinking lake unthinking something like name right so every student in our programs should have a name. they also might want to have a major because they're in college, they probably also will have a gps, so their grade point average like how they're doing in school and lets to find one more thing that let me think, why don't we make a bullion and it's going to be called is on probation and this will basically tell whether or not the student is on probation. so essentially what I'm doing inside of this initialize method inside of this innate function is I'm defining what a student is in our program. and so in this program a student has a name, it has a major as a gps, and it has a value that determines whether or not it's on probation. this right here is the student data type. so if I'm representing a student inside of my program now, it has all of these attributes associated to it. and that's basically what I'm doing up here now inside of this initialize function we actually have to do something and basically what I want to do is assign some values so I'm going to be writing out some stuff and this might not make total sense right now. but this is going to make sense in a second after we create our first student object. so just stick with me right now and just basically know that we have to do what I'm doing over here so I'm just going to say self dot meme is equal to name. and then I'm going to say self dot major because you get the major self dot gps is used the gps. and I'm going to say self dot is on probation is equal to is on probation. so again this might not make a whole lot of sense right now but in a little bit this is gonna make total sense so now that I have this student class defined I can actually use this class inside of my other file so I'm gonna come over here into this app dot python file. and this is just my main file. so I actually want to create a student right so in that student class we defined the student data type and we basically said like hey a student has a name, a major a gps and it says whether or not they're on probation dots like the template for what a student is, but we can actually create a student so we can create an actual student and give it some information. and that's called an object. so this student class over here is basically defining what a student is so a class is just like an overview of what the student data type is an object is an actual student so it's an actual student with a name a major and a gps. it's not just this template anymore it's actually like a student that we're representing inside of our program so in order to use that student class and create a student object I actually need to import that so all I have to do over here just say from student and this is referring to this student file. I can say import student and basically what this is saying is from the student file. I want to import the student class. so even though these are both student they're referring to different things so this is referring to the file. and this is referring to the actual student class. so now that we did this we can create a student so you can create an object of a class a lot like you would a normal variable so I can just give it a name I'm gonna call this student one and I'm going to set it equal to student and I'm gonna make an open and close parentheses and now inside of this parentheses. I want to give this student a name, a major a gps and ann is on probation value. so I'm going to say it will just create a fake student saw to say his name's jim and he's studying business and we want to give them a gps and maybe has like a three point one. and finally we want to say whether or not this student is on probation so why don't we say false. so basically what I'm doing is I'm saying that I want to create a student. so I want to actually create a student object and rubber an object is just an instance of a class. so the class is like an overall template it defines what a student is put an object is an actual student with actual information so we could call student one now this is a student objects. so I just want to show you guys, what this student object actually is and what we can do with it and then I'm going to talk some more about that in it function from before so over here I'm just going to make a print statement inside of here I just want to print out student and what's cool about this student one object is I can actually access each of the attributes from inside of this object. so if I wanted to get the name of the student I could say student one dot name and now this is actually going to print out the student's name. so over here, you'll see it prints out jim if I wanted I could print out the students gps and it's going to print out the students gps three point one. so now that I created this student objects. I can actually access the information about the student so essentially I'm just created a student data type so I could create as many of these students as I wanted if I wanted I could create another student we could call it student too. and essentially we do the same thing we just give it different information so we could say lake pam and her major is art and she has like a two point five. and let's say that she is on probation. so now I have another student student too so if I wanted I could access information about that student we could say like student to dodgy p a and now this has given me the dpj of student too. so basically what I did was I created a student data type and I created student objects and now I'm able to represent a student inside of my program. so let's talk real quick about all this stuff over here because I didn't really explain it basically what's happening is when I come over here and I say student and I'm passing in all of these different values. those are getting passed into this init function. so remember I passed in a name I passed in a major at passing a gps. when we create that student we're actually calling this function. and when I pass in the name the major and the gps those values are actually getting stored over here in this name. this major this gps et cetera, right so I'm giving this student object. all of that information. and down here. what I'm doing is I'm saying self dot name as he put the name and basically what this means is the actual objects name is going to be equal to the name that they passed in so self dot name as an attribute of student, raises the student is storing a name the student is storing a major the student is storing and gps, but that's different from this name this major in this gps remember and these are all just values that I passed in there just parameters. so I need to take the values that I passed in and I need to assign them to the actual attributes of the object so I need to say ok. the name of the student is going to be equal to the name that we passed in one more time. the name of the student objects is going to be equal to the name that we passed in the name of the student's major, is going to be equal to the major that we passed in the student's gps is going to be equal to the gps that we passed in. that's basically what's happening here so when I say self is referring to the actual object so over here what I'm creating this student object. I'm giving it all of this information. it's taking that information and storing it as attributes for the object. so hopefully that makes sense I think that's about as clear as I can make it but the point is that now we have a student data type. so now I can represent a student inside of my python program and that's like a super powerful. and what's cool about classes and objects as you can do this with anything. so in this example we created a student class and then we created student objects off of that. but I can model any real world entity into this program I can model something like a phone or I can model like a water bottle or I can model you know a keyboard or I can model anything that I wanted. inside of my program I can just give it certain attributes right so that's what's cool about classes we can model real world objects. and we can create our own data types in this tutorial I'm gonna show you guys how to build a multiple choice quiz in python. so basically we're gonna set up a little multiple choice quizzes and we'll have the user take the quiz and as they take the quiz will keep track of their score and then at the end will tell them how they did so this is going to be a pretty cool video I'm excited to show you guys how to do this and we'll get to use things like classes and if statements and loops in order to build these programs are we're going to use a lot of cool stuff in python. the first thing I want to show you guys actually did this before I started the video it's this little a ray is called question prompts. and I basically just wrote out all the questions that are going to be. or I should say the questions I wrote out all the question prompts that are going to be inside of my multiple choice quiz so the first one just says what color are apples and the answers are red, purple or orange. and the next one is what color of banana is the options are teal magenta and yellow, and the third question is what color are strawberries and the options are yellow red and blue so this is obviously a very very easy multiple choice quiz but I just kind of wrote out the questions beforehand so I didn't have to spend time doing that. so let's talk about how we can build a multiple choice test. well. the first thing I want to think about is how can I represent the questions in the test right over here we have the question prompts. but there's actually two parts to a question when you think about it, there's the prompts in other words like the actual question itself. and then there's the answer to the question in both of those attributes needs to be kept track of right I need to keep track of what we want to ask and I need a cap to keep track of what the answer is. so what I'm actually going to do is create a question class so I'm gonna create a little data type for questions and inside of that question class will be able to store the question prompts, and will also be able to store the question's answer, so I'm just gonna come over here to my folder and I'm going to make a new python file and we're just going to call this question dot p y so we'll call a question up high and inside of this question dot pi file I'm going to make a class so I'm just gonna say class question. and I'm going to put a colon here. so inside of this question class we want to define it and initialize function so I must say deaf to underscores in it too underscores, and then we're going to type out an opening close parentheses self and that a colon. so after this self we wanted to find the different attributes that will describe or that will be included in a question so we're going to include a prompt everyone to include an answer so every question we'll have a question prompt and a question answer now down here I'm going to take those values and assign them to the actual class objects only to say self dot prompt is either the prompt. and I must say self dot answer is equal to answer. so now we have a question class set up and we can store all the information we need about a question. so what I want to do now is go back over to my app dot python file, and we're actually going to create an array of questions. so I have over here these three prompts, and I'm actually just going to create another array so we'll just call it questions. and I'm going to set it equal to to open or closed square brackets and we're gonna start creating question objects so I can just say the first element in this questions ray will be a question, and we want to pass questioned prompts zero. and the answer to the first question was a red green and that's the color of apple so I'm gonna pass that first question. and I'm also going to pass the answer which is a, and you see down here I'm getting an error so seeing unresolved references question so actually what we need to do before we can create these questions is we need to import this question class on mckillop been here come up here and say from question import question so now down here in this questions array we're not getting that hair anymore so we created one question objects. and I'm just going to create a couple more for these other ones so I'm just going to copy this one and we will pace this down here, or it's an hour creating two other questions in these ones are going to be one and two. and the answer to the second question is c. and the answer to the third question I think is that the new york yeah so it's cmb. so essentially what we're doing is we're creating three questions. each one is getting a different question prompts, and they're each getting different answers so now we have an array of questions that we want to ask on our test. so the next step is to actually write a function that will run the test right it has to ask these are the questions and it has to check to see if they got the answer right so down here lower in the file let's create a function. so I'm just going to say death. we'll call this run test and inside of his prentices were going to take one parameter into this function. we're going to take a list of questions so I'm just going to say questions. so this is basically going to be a list of question objects that we want to ask the user. so once I've been here all I want to do is a loop through all the questions so I want to loop through each question I want to ask it to the user. I want to get the user's answer and I want to check to see if it's right, and we need to be able to keep track of how the user does through the test so I'm gonna create a variable called score and I'm going to set it equal to zero, so every time the user answers a question right will increment this score variable right so what I want to do is like I said loop through all the questions in that questions array so I'm going to create a for loop I'm going to say for question in questions. so in other words for each question object inside of this questions array. I want to do something. and basically the first thing I want to do is ask the user the question and I want to store their response inside of a variable. so I'm going to say I wanna make a variable down here called answer. and this is going to represent the user's answer to the question. and I'm gonna set it equal to input and I need to give this a prompt so I'm actually going to give this the prompt for the questions I can just say questioned dot prompt. so now I have the answer that the user entered in which is stored inside this variable. so we want to check to see if they got the question right. and I can do that using an if statement so I can say if answer and this refers to the student's answer is equal to question dot answer so I'm checking to see if the answer that the student gave as equal to the answer of the current question that we're asking. and if this is true, then I just want to increment score so I'm going to say score plus equals one and this basically just means we're adding one to the score. so the last thing I want to do inside of this function is just print out the results I want to print out how the user did so down here I'm just going to say, print and I'm basically just going up are not like hey you got like two out of three questions are you got five out of six questions right or you got zero out of ten questions right well what does per not how they did so to say to you got. and now I want to print out how many questions they got right so this is just going to be this score. and in order to print a number alongside of a string like this I'm going to have to say s t r, and then type in the number so say str score so basically say you got however many they got right out of so we use this little forward slash. and now we'll just say how many questions there were so we can say. and then I'm going to have to convert this to a string because it's going to be in numbers we can say string and then want to figure out how many questions were in that questions array so I can say. ellie ann and inside of here we can just say questions so this is kind of like this long state and just to turn out how many questions that were so that over here to say correct. so now we have this print statement. and it's just going to be printing out how many questions they got right. so let's see if this works the last thing I need to do is just call this run test function so I'll say run tests. and I'm just going to pass it that questions are ready to be created before so we created this questions array with all of these question objects inside of it. I'm basically just going to pass that into this run test function. so now let's run our program and see how we didn't hopefully we don't getting errors. there's a lot of code there so it's possible that we might. okay so this is what color are apples has a tough one I once put a. so we'll get the first question right ? what color are bananas. let's get the second question wrong so I'm going to say be bananas aren't magenta and we'll get the third question right so it says what color are strawberries output be cassettes the right answer, so now you'll see that our program prints out you've got two out of three correct. so not only did to ask us all the questions and get our input for each question but it also kept track of our score and it printed it out so why don't we run through the tasks one more time. and we'll just like get two wrong this time so we'll get this one wrong I'll get this one wrong and I get this one right. so now it says you got one out of three correct so say would actually great our test. and what's cool about the program we just wrote is if I wanted I could add another question into here and it would automatically be able to ask it so it doesn't matter how many questions we put in here it's just able to ask so really the point I was trying to make with this whole video was just how we can use something like a class in order to model a real world entity. so for example we created this question class. and we were able to store all the information about a question that we could ever needs were ill bizarrely the prompts and the answer, so we created our own question data type and then we were able to create a bunch of different questions, pass it into this ron test method, and it was able to grade the test and just run the test really easily so that's kind of the point. so hopefully this makes sense. you know this was a lot of code so if you don't fully understand what I did go back watch the video you know, try to cobble times on your own and see if you can create your own multiple choice test in this tutorial on talks you guys about class functions in python so a class function is essentially a function that we can use inside of a class and it can either modify the objects of that class where it can give a specific information about those objects. over here I have this student dot pi file and inside of here I created a student class I was headed class student and I gave this student a couple of different attributes I gave it a name, a major and a gps so I can give this student. all of this information so when I create a student objects. it'll have all of that information in it. now over here on this app dot pi file it actually created to students so student one is oscar who was studying accounting and has a gps unit three point one student to as phyllis who's studying business and she has a three point e. so what we can actually do is we can use functions inside of these class files so I can actually define a function instead of this student class and then all of my student objects could access it. so for example, I can come down here and create a function and let's say we wanted to create a function that told us whether or not this particular student had honours so whether or not they were on the honor roll right basically like, are they like a really good student so I can define a function call on honor roll and basically what it's going to do, it's going to tell me whether or not this particular student is on the honourable and let's basically just say the rules are being on honor roll is you have to have a gps iif three point five or above. so here gps three point five or above that means you're on the honor roll well over here I could actually write the code for that so I could say if self dot gps. and when I say self over here this is referring to like the actual students gps and you'll notice over here I have to pass that in as a parameter. and that always has to be the first parameter so I could say if self dot j e p a is greater than or equal to the read point five. then we can return true because this student is on the honor roll otherwise an else we can just return false because if their gps isn't above a three point five that they're not on the honor roll. so that's essentially our little on honorable function and you can see it's a very small function, but it provides a service to the objects of this class right it allows the objects of this class to figure out whether or not that current student is on the honor roll so over in this app dot pi file. I could just print out that values so I could say print and I'm gonna see if student one is on the honor roll. so now when I run this you'll see it should print out false and is putting out false down here because student one only has a gps of three point one. if I was to do the same thing on student to students who has a gdp of three point eight so we should return true. and that's exactly what happens so essentially a class function is just a little function that can be used by the objects of the class and I would say this is a pretty good example of what a class function should be doing should be like giving us information about the class or it could also be like modifying information about the class. and so that's the basics of using functions and classes I mean this is a pretty simple tutorial but I really just wanted to introduce you guys to the concept of pudding met functions inside of classes this is going to be really useful and if you're making a class you always wanna think about like what functions can I put inside of here that will you know essentially healthy user to either figure out information about the object or modify different values in the objects in this tutorial on antarctic guys about inheritance in python. inheritance is basically where we can define a bunch of attributes and functions and things inside of a class, and then we can create another class and we can inherit all of those attributes. so I could basically have one class that has all the functionality of another class without having to physically write out any of the same methods or attributes. so it that's confusing don't worry I'm sure you guys exactly what this is in this video so let me show you about some stop I have set up over here. I created this class called chef and over here we just have this class chef. and inside of this chef class we have three functions so the shaft can do three things. the chef can make chicken. the chef can make solid and the chef can make a special dish. and whatever the chef makes a dish he basically just says the chef makes a chick in order the chef makes a salad or the chef makes barbecue ribs for this special dish. so basically just saying whatever the chef is doing so if I was to come over here to my app dot python file, you'll notice that I'm importing the chef so I'm basically allowed to use this chef class now, and I can say my chef is equal to shafts I'm creating a new chef. so now if I came down here and I send my chef dot make chicken, when I run my program. now it's going to say, the chef makes a chicken. if I said make special dish and are on the program. now it's going to say the chef makes barbecue ribs so it because that's the chef's special dish. so I have this really awesome chef class and it works really well. but let's say that I wanted to create another class to model another type of chef rise to this chef class is just modelling like some generic schafroff we're representing some generic chef in our program, but let's say that I wanted to create a class that modeled the different type of chef for example, let's say we wanted to create a class that modeled a chinese chef. so instead of just a normal chef this is a chinese chef, well I actually created a file over here called chinese chef dot python. so we can actually use this chinese shaft out python file to create our chinese chef class tom's going as a class. and over here I'm just going to say chinese chef and basically I just can define everything that the chinese chef can do, but let's say that our chinese chef can do everything that are generic chef can do. so the chinese chef is like a special schafroff it's very specific type of chef. but let's say that this chinese chef can do everything that the normal chef can do so the chinese chef can make chicken can make salad, and can also make a special dish. well if I wanted to give this chinese chef, all of that functionality. I could just come over here and I could copy all of these functions. and I can paste them in here and so now the chinese chef can do everything that the other chefs can do, but let's say that in addition to all of these things the chinese chef can also make a special dish called fried rice so I could say deaf and we could say make fried rice. so the chinese chef has this extra function which allows it to make fried rice. and over here we just say, the chef makes fried rice. and let's also say that the chinese chef has a different special dish so instead of making barbecue ribs. the chinese chef makes lunge chicken. all right so now we have our chinese chef class set up and you'll notice that it can do everything that the normal chef could do. so let's go back over to our app dot python file and I want to create a chinese chef object. so instead of importing from chef we're going to just import it from chinese chef. so I'll say chinese chef and we're going to employ for chinese chef. so let's go ahead and make a chinese chef object sit down here I'm going to make one arrow to say my. and then my chinese chef. we can print out this special dish so remember the chinese chef can do everything that the normal chef could do so if I say my chinese chef da make special dish. when I run this program you'll see the regular chef is making barbecue ribs and the chinese chef is making orange chicken so everything works out. and this chinese chef also has an extra method called make fried rice. and you can also make fried rice. but here's the problem right when I go over here to this chinese chef dot pie. I went I wanted to use all of the functionality that was inside this chuffed class I actually had to copy and physically paste. all of these functions down into this file right and that's kind of a drag. and they especially like imagine if this chef had like twenty or thirty of these different functions in it. we have to copy and I have the pace. all of those inside of this chinese chef and this is where we can use something called inheritance so instead of having to copy and paste all of these functions. I could just inherit these functions from that chef class and in order to do that, I can actually just get rid of all of these, and I can come over here and right next to where I'm saying class chinese chef inside of the parentheses I can say the name of the class that I want to inherit from so I can just say a chef. and I'm also going to have to import this song to come over here and we'll say from chef in poor shelf. so basically what this is saying is inside of this chinese chef. I want to be able to use all of the functions that are contained inside of the chef class so say that one more time inside of this chinese chef class I want to be able to use all of the functions that are inside of this chef class so by using inheritance here I'm actually able to come over here to this anecdote pi file. and now I'm still able to execute for example like the make chicken function. even though I didn't specify the make chicken function in here I didn't write it out. I can still run this program and the chinese stuff. the chinese chef will still be able to make chicken. so when I run this program you'll see it out here it says the chef makes chicken and that's because I inherited the make chicken method from the chef class but here's one thing that got my stuff if I come over here and I say make special dish. remember the chinese chef special dish was supposed to be orange chicken. but now the chinese chef is going to be making barbecue ribs because I inherited this makes special dish function from this chef class is what I can actually do is I could come in here and I could override that make special dishcloth so I could say death make special dish. and down here I can just override it so I could say, the chef makes orange chicken and now when I go over here and I run this make special dish function. now the chefs are going to be back to making orange chicken so the chinese chef will make his special dish. so that's basically what inheritance does it allows me to inherit functionality from an existing class into the new class. and I can actually just inherit all of it without having to write it out so I didn't have to write out make chicken and make solid inside the chinese class, but the chinese chef can still make chicken and salad because it inherited that functionality from the chef class in this tutorial I wanna talk to you guys about the python interpreter. the python interpreter is basically a little environment that we can use to execute python commands. so it's kind of like this little sandbox environment where we can test out and try out different python commands are different python functions in a very safe and neutral environment. so it's kind of like a quick and dirty way to write python and try different things out. the way we use the python interpreter is by opening up opening up our command prompt. now if you're on windows there's a program called command prompt if you're on mac there's a program called terminal. basically you need to open that program in order to use the python interpreter, so I'm here on a mac but if you're on a window as you can essentially do exactly what I'm doing just inside of the command prompt. so on mac here I'm just going to search for my terminal. if you're on windows you can just search for like cmd or command prompt in it should pop up, so the terminal is basically an environment on our computer where we can interact with the computer and do different things without a graphical user interface so normally when we interact with the computer we're using things like buttons or you know windows and you know what we can move stuff around we can you know basically just like interact with the computer. with graphics with the terminal or the command prompt is a place where you can interact with the computer using text commands. so you know am I going to get too much into what the terminal the command prompt dog but that's essentially what it is. so inside of here, we can use the python interpreter and the python interpreter is basically just a little program that like I said and we can write you know sort of python in so generally, all you have to do is go over to your terminal or your command prompt and type in python three and since we're using python three on monotype python three. but you can also just like normal python and I'm pretty sure that gives you python two. now here's a quick disclaimer. I'm on windows, you may run into a problem where you can't use this python three command, and it's possible that if you're running into that problem python python three hasn't been added to your windows path variable. and basically what that means is your computer doesn't recognize the command python three and that's the case all you have to do is just go and google how to add python three to your windows path variable. it's really easy I'm not going to get into it in this video just because it's kind of outside the scope but if you're running into that problem. that's probably it's not on your windows path variables such as google around for that and you should be able to find an answer, but onsite python three and then click enter and it's going to open up this cool thing down here so you can see it basically just says like here's the version of python. now I'm going to enter so we can have some like new lines here and put down here this is the python interpreter so we can write python code in here and it's going to work so I could for example I could write like print and inside of here I could print like hello world. and when I click enter you'll see that it prints out hello world. I could create a variable so for example I can say like number one is equal to ten. I can say numb two is equal to ninety. and then I could print out number one plus none too and it's going to be able to do that for me ? I could also use awesome like a function so I can define a function in here, we can make a function that is called say hi and it'll take a name parameter. and you'll see here when it saw I wanted to create a functional put these three little dots and I can index in and we can write the code for a function so I can say like print hello last name. and now I have a function called say hi so I can break out of this by this entering again and I would call the function so I could say say hi and we'll say out of me. I'm like so now it's going to say hello mike so I can use a function I could use something like an if statement you know I could say, I can easily afford the wicked use while loose. I mean we can basically use all of the basic like python commands and you know inside of this python interpreter and like I said before. it's essentially just an environment where you can test out python code. now this is not a place where you want to write like any serious python scripts so if you're like designing and writing a python program I would not recommend doing it inside of this interpreter ? it is, it's not a very intuitive environment it's pretty much just set up for some quick and dirty tests we need to test somethin' out great this is a perfect place for it. you'll have to set up a file you'll have to use like some id you don't have to execute a filing is going here it's quick it's dirty, you get it done. but if you're writing an actual program. you definitely definitely definitely want to use a text editor. the text editor is just going to be way more organized everything is going to be a lot cleaner and you're not going to get confused with like where stuff is and what you have so that's the basics of the python interpreter, you know in the course I havent really been using it at all, just because I think it's a lot easier to teach when we're inside of a file, then inside of here but you know don't count this guy out the python interpreter is awesome a lot of people who use it and it's great if you just need a task you know little bits of code out without having to set up some huge environment so python interpreter definitely awesome out player out there you know have some fun and take advantage of it. hey things are washing if you enjoy the video please leave alike answered garbage off academy to be the first snow and release new content also were always going to improve so if you have any constructive criticism or questions or anything leave a common below finally if you're enjoying job academy and you want to help us grow head over to draft academy dotcom ford sauce contribute and invest in our future.

Channel: freeCodeCamp.org

Views: 23,759,406

Rating: 4.9577351 out of 5

Keywords: python, python tutorial, python language, python full course, python course, learn python, learn python programming, python tutorial for beginners, python tutorial 2018, python programming tutorial, python programming language, software development, programming tutorial, freecodecamp

Id: rfscVS0vtbw

Length: 266min 52sec (16012 seconds)

Published: Wed Jul 11 2018