2D Arrays in Java Tutorial

2d arrays in Java can be kind of hard to understand especially for beginners so in this video I'm gonna teach you how to use 2d arrays in Java and do an example of how to use 2d arrays for a lottery ticket hey it's Alex back again helping you code quicker and easier with program examples on this channel I make tutorials just like this all the time so if you're new here consider subscribing so you may have heard of 2d arrays and you may have thought what the heck am I using these for is this just supposed to make my life a living hell for the exam well that's exactly what I thought when I first started but there's actually a good reason why you're learning it the screen you're watching this video on is a 2d array of pixels probably 1920 by 1080 or something like that and each of those pixels has its own RGB values making it light up different colors and make different patterns on the screen and having a set of rows and columns of RGB values like that makes it really easy for computers to refresh all the time and show videos like this so anything with rows and columns can be stored as a 2d array it's like having a quick table you can access all the time so let's do that lottery ticket example of 2d arrays in Java I did a video covering normal arrays in Java just 1d arrays so if you want to check that out you can click it here on the link in the card and it's also in the description so let's go ahead and make this lottery ticket example so go to file new Java project we'll just call it our lottery ticket ticker pick it and it finish then go under it click source go to new class and this will set up our Java file we'll just call it lottery I cannot spell the date guys lottery ticket ok and public static void finish boom we're done ok now we actually have to code it to make a 2d array in Java it's really simple first we think about what values is it gonna have well our lottery ticket usually has integers so we'll do integers so we just type int and then 2 boxes just like that and we'll name it our lottery card and we'll set that equal to the values in our 2d array of rows and columns so we'll just slide those in some curly braces and we'll do the first row the first row has curly braces 2 and we'll just set up our numbers well have it be 3x3 of just some random numbers and we might have like 7s going diagonally we have our first row here and then at a comma and just for simplicity sake we'll try that I'll line it up a little bit at the second row of numbers just like this okay we have our second row and then the third row just some more numbers like that and you just store it a 2d array now that's one way to do it you can also make a 2d array in Java just like this we'll call it our lottery card too and we actually just set the dimensions here so we say it's three rows and three columns wide and we actually have to put the keyword new here please excuse the really loud train outside its State Fair season and I live on the fairgrounds so I have to sit in 30 minutes of traffic just to turn right into my house with this we have the problem with this way is that in order to store the values you have to manually do it like this I would set the first row and the first column value to 20 and then I go in here again and say the first row the second equals 15 and you'd go all the way down and you to end up with something like this the numbers inside of these boxes or the square brackets are the index and index is always start at 0 so that's why you see 0 0 is 20 like that and then 0 1 which is actually the second one is 15 and it will always go row-column and one way I can remember this is array starts with a row so that might help someone know so let's prove to ourselves that this is actually working let's print some stuff to the screen and we'll print let's say the first value so let's try to get this 20 out of the law degree card 2d array so we would let's make this a little bigger as you can see so we get our lottery card which is the name that is actually this 2d array we could just refer to it by the name and then we would go into it by typing our square brackets go to the first row and the first column and if we run this we should get this 20 let's try that now we get the 20 if we wanted to print out all of the values here I'm just gonna add some space here for the next thing we're gonna do if we want to print every single value out of a 2d array we can go through it with something called a for loop I haven't gone over this on my channel don't worry about like how to type this just follow my lead just like that Cody nerdy stuff there decoding stuff don't really worry about what's going on I'll explain everything okay here's an example of printing out multiple values out of your 2d array now this won't get every value but I kind of just want to show what the idea is here so let's save it and run it we see our little divider we print it out and then we see 27 and 47 and that's actually this diagonal right here I'll be going over for loops in a separate video so don't worry about this but in a nutshell we're pretty much running this code three times and this variable I is changing we're getting the element 0 0 and then in the second time we're getting element 1 1 and the third time we're getting element 2 2 so that's why it's putting this diagonal 27:47 and then 2747 ok let's try to get out all of the elements in this array I'll add another divider so instead of having IV the same one this will print diagonal we want to indexes so we can go all the way across and it's kind of hard to understand don't really worry too much if you don't get the whole thing you'll get it eventually because I'm gonna make sure that everyone on this channel gets the proper coding knowledge that they deserve because I know when I was learning how to code all this was like so foreign to me I had no idea how like the TAS or the teachers did it it was just it was really hard for me so that's my goal on this channel to try to help you guys out ok and now here we'll go into our array and put I and J this piece of code right here will print out everything on the first row than the second row then the third row so if we save it and run it we'll see that a third little divider here you got 2015 7 and let's see if that's right yeah we got 2015 7 and then 8 7 1987 19 and 7 13 14 15 so this is just a little example of a 3x3 lottery card with like the 7s going agonal II and we won on the jackpot question of the day do you have any assignments or projects related to 2d arrays in Java connect with me in the comments and engage with this community of new programs just like you make sure to subscribe so you see all my videos the day they come out if this was helpful smash that like button and share it if you think it might helps when you know you could be anywhere in the world but you're here with me and I appreciate it catch

Channel: Alex Lee

Views: 165,806

Keywords: 2d arrays in java, java 2d array, two dimensional array in java, how to use 2d array in java, 2d array java, 2d arrays java, java, how to use a 2d array in java, how to use 2d arrays in java, how to use a 2d array java, how to make a 2d array, how to make 2d array, how to make 2d arrays, how to use 2d array, how to make two dim array java, how to make a two dimensional array in java, 2d array of integers in java, alex lee

Id: L3-q2GxAqZA

Length: 8min 34sec (514 seconds)

Published: Thu Oct 25 2018