How to use LIBRARIES in Pine Script V5

hey traders welcome back to another panscript lesson sorry it's been a little while i've been extremely busy trying to re-record and edit and prepare the version 5 mastery course content hopefully i'll have all of that done within the next few weeks for those of you who are interested in diving deep into version 5 of panscript there's a lot of cool features that tradingview have added to this language i'm excited to explore them with you guys so make sure to hit the subscribe button if you haven't already because i promise to come back real soon with more content covering version 5 of panscript and all the new features and functionalities and syntax in great detail but for today's lesson i thought it might be interesting to explore the new library feature of panscript version 5. so today's lesson is going to be taken from my indicators and strategies course where i explained to students of that course how i wrote this library and what it all does because it's a public library and i had to publish this publicly so it is an open source script i figured i might as well throw this video up on youtube as well because i'm sure a lot of you are very interested in finding out how libraries work i know why i was when this feature was first released so as always there will be links in the video description to this script so that you can go and get the source code if you want um and any information resources i mentioned in today's lesson will be there and without further ado let's get into today's lesson it's going to be a longer one because there is a lot to cover here so grab yourself a coffee or a beer or whatever it is you need in order to take this information in today and let's get started this script is a library which means it is basically a reusable script a script that can be referenced by other scripts now it behaves a little bit differently to indicators but that is what it is most similar to you can use most of the features of indicator scripts in libraries but there are a few important differences which we'll go over in this lesson and in other lessons so the zen library is just a collection of custom tools and utility functions commonly used with my scripts so i wrote this library to assist in my own scripts so all of the functions you see here are just functions that i commonly use across multiple scripts and so i can keep all of this code in one place reference it in my other scripts and if i need to make an adjustment to anything if there's a bug with one of these functions or i need to add a feature to one of the functions i can do so in one place and that will work across all of my scripts now before we begin breaking down this script we should probably go over the core fundamental basics of what a library is and how libraries work so here i am on the blog post that announced the new version 5 of pinescript so libraries are a new type of publication that allows you to create custom functions to be reused in other scripts once a library is published other scripts be it indicators strategies or even other libraries can import it and use its functions so this is a great new addition to pine scripts if you're familiar with other programming languages libraries can be thought of as modules or classes in java basically it's a self-contained script that can be exported to other scripts so we can reference whatever our libraries do in other scripts so before we move on let's have a quick look at the user manual page on libraries and we can go over some of the features and limitations of libraries so here is the official documentation for libraries i'll leave a link to this in the video description some important things i should mention up front is that a library must be published privately or publicly before it can be used in another script and you cannot use private libraries in public scripts so you can use private libraries in private scripts but not public scripts if your script is published publicly you cannot reference a private library now to create a library is very simple we just use the library keyword or annotation function when creating our script so normally this would say indicator or strategy now we have a third script type to work with and that is library so if you define your script as a library it gives you access to all the features of library scripts now another important thing to mention are all of these annotation comments or compiler directives which are all optional but they do help document your library's code and populates the default library description which authors can use when publishing the library so basically when you're creating your functions you can explain it using these comments what your function does what parameters it takes and what your function returns and then when you publish your library all of this information will be put into your script description so for example here is my trading view profile if i scroll down to my scripts list and i click on zen library if i scroll down here you can see that all of my functions have detailed descriptions in the script website description i didn't need to write any of this when i published the script it was all taken out of my script code so by now if you've been following my channel for a while or you're a student of one of my courses you should know that i always highly encourage you to heavily comment your code it makes it easier to read both for yourself and for others if you share your code and in libraries that is extremely encouraged because libraries are obviously designed to be used by other traders or coders so i would encourage you to get into a habit of using these comments even though they are technically optional what is not optional is the export keyword now i'll cover this in the lesson today but it's important to mention that if you want your function to be accessible by other scripts when they import your library you need to use the export keyword to tell panscript that this function you are creating is intended to be exported to other scripts if you don't use the export keyword then your library function will not be accessible by other scripts the next important thing to mention is that you need to explicitly define the data types you are using in your exported functions so normally you could just create a function with a parameter variable name and you wouldn't need to explicitly tell panscript what type that variable is in libraries things are a little bit different we now have to say explicitly what data type the parameter is that we work within our function this makes it so that when people use our library code they can't pass in an invalid data type there are a lot of new answers to the data types we can use in libraries i'm not going to go into that in too much detail in today's lesson because it'll just make the lesson far too long but i will be covering this information in great detail in the upcoming version five of the pine script mastery course which will hopefully be ready within the next month or two finally the last important thing to mention is that there are certain things we cannot do with libraries we cannot use the request library inbuilt library so we cannot use the security function to reference other markets we cannot get user inputs and we cannot use plots fills or background color calls in our script aside from that let's wrap up this introduction to libraries by showing you how you import libraries so once you've publicly published your library or privately published your library like i have here the way you import this code into your script is using this little link here so if i copy this and jump over into the pine editor here we are with a blank script if i add in at the start of my code this or if i paste in this little import link that i just copied we can now reference the functions from this library one important thing to note is that we can also import this with an alias so i can say here import my zen library version two so i had to update the library since creating this video originally because i had to fix a minor bug in the code so i'm working with version two of my library now and i can import this as zen and now when i type in zen and then a full stop and then hit control space or command space on a mac we get my list of functions from my library so for example if i want to detect a bullish engulfing candle i can say bullish engulfing candle equals zen dot is bullish ec or engulfing candle and i can plot a shape i can say is bc true then plot a shape otherwise plot nothing now if i set overlay to true save the script and add it to my chart we're now getting a shape plotting above engulfing candles all of that with one line of code instead of having to write out my candlestick pattern detection which is usually multiple lines of code and requires user inputs and all that sort of thing if i hover over this function you can see that i do have a bunch of optional parameters here we can work with and if you go and read the documentation that was publicly published along with this library you can find out exactly what all of those parameters do anyway that's it for the introduction to libraries how they work some of their limitations let's get into today's lesson where i break down my source code to my zen library public script i hope you find it interesting and i will be back soon with more version 5 pan script content once i get done with recording and editing more of the mastery course content let's get started with today's lesson so let's get started with the utility functions so here are just a handful of simple basic utility functions and now this script is heavily commented because when you publish library scripts all of this information here gets converted into your script description so that other traders when they scroll through the script library they'll see exactly what your script does i'll show you that really quickly so here is my publicly published library script and if you scroll down a bit you can see all of the information all of those comments in the script get converted into the script description here and so anyone who comes across this library in the trading view public script library we'll see exactly what my script does so they can just read through the documentation here and understand what each function does without needing to read through the code to work that out so let's go over some of these utility functions the first one we have here is get decimals now notice that you need to use the export keyword or prefix to declare functions that will be available from other scripts importing the library so you can have a function in here like my function whoops that was not even close to correct and this function could return x and i could call this function in my script so i could call my function down here and now if i say the script uh we'll get an error because this x doesn't do anything let's just say x equals one and save the script and that compiles just fine now the main difference here is that we cannot reference my function in a different script so if i throw on a new blank indicator here and i go to my library link copy that go back to my blank script and paste that at the top here now i can import this with an alias so let's say as zen so now i can reference the library by saying zen dot control space and that will give me all of the functions in my library now if i were to publish this script this function exists within the local scope of our library no other script could reference this function because it is not exported so in order to reference functions within this library we need to use the export keyword to make sure that pinescript knows that this function needs to be exported and able to be referenced by other scripts now the reason we do this is because there are certain rules with exportable functions that we need to respect for example we cannot use the security function with libraries now if you want to read about all the nuances and limitations of libraries come to the user manual panscript version 5 user manual there'll be a link in the video description they explain exactly how functions work i'll be recording a lesson on libraries in detail in the mastery course but the main important things to note is this section here we cannot use request so we can't reference the security function um or anything else that falls under the request library we cannot get user inputs we cannot plot fill or use background color calls i'm not sure why but that's just the rules for library scripts but anyway that's outside the scope of today's lesson let's just break down the functions that do exist in my library script um so i already mentioned get decimals get decimals gets the decimal places after the quote price on your chart so in this case i'm on bitcoin and there are two decimal places after the quote price so using this function would return two this is useful for things like truncating a number down to the same number of decimal places on your chart so some scripts maybe you're sending a web hook alert to a third-party api and you send an indicator value or stop-loss price or something like that and the price might look like something like five-point and then like seven or eight decimal places after the uh number and maybe you only want to send the same number of decimal places as the market you're on that is what this is useful for and this function the truncate function the get decimals can be used with the truncate function to cut the excess decimal places off numbers in your script then we have the two-hole function which just converts pips into whole numbers so if you've got for example if we're on euro yen and we want to calculate a 50 pip stop loss 0.52 would be converted into 52 as a whole number and then we have our two pips function which just converts whole numbers back into pips next we have our auto view get position size function so this calculates our orlando forex position size for order view based on the given parameters in the function arguments so we have balance risk stop points and conversion rate so if you pass in your account balance your risk per trade as a percentage you'll stop loss size in points not pips so if your stop-loss size is 10 pips then you would put 100 points into this argument and then we have our conversion rate which is the conversion rate of your account balance currency against whatever you're trading or whatever you've set your alerts on and this function will return your position size i put it in this library because i try to automate all of my scripts that detect profitable signals and this just makes it a little bit easier to do that without having to copy this code into every script that i write now moving on we have our technical analysis functions so these just get various values relating to technical analysis so the first one is get ma this gets a moving average based on the given type so you could pass in ema sma hma a weighted moving average wma vwma vwap or a dema that's what this last one returns so in my scripts i usually let me throw on the ultimate pullback indicator really quickly and open up the source code if i come up to our moving average settings i usually have my ma type as a user input and then we have our list of potential options here and then i can call this library getma function to return a moving average based on that setting i use moving averages in a lot of my scripts and so it's helpful handy to be able to get those moving averages using this library really easily without having to have all of this code in my script next up we have get eap this returns a stop loss size based on the eap stop-loss sort of algorithm or formula that stephen hart from the trading channel uses in his strategies basically this is just a way to round down your stop loss based on certain brackets so that you can have a slightly tighter stop on average and therefore a slightly larger position size on average leading to slightly improved profitability on most markets at least or most strategies while not affecting your stop-out rate too much or your loss rate too much so first of all you pass in your current atr then the script converts that number into a whole number using the two-hole function from up here so it's referencing its own library function here and then we declare our eap stop whole number variable and then all of these if statements just check if the atr falls between 20 pips and 30 pips then it sets our eap stop loss to 20 pips so if we had a 29 pip stop loss this function would return 20 and our stop loss would be 20 pips above the high instead of 29 pips and so on 30 between 30 and 50 it gets rounded down to 30. between 50 and 100 it gets rounded down to 50 and anything over 100 gets capped at 100 pips so that's what this function does now i use this in my scripts a lot but if you're not a student of stephen hart and you're not familiar with the eap stop-loss sort of algorithm and why he uses it maybe don't use this in your own scripts unless you understand the concept here so moving on we have our bars above moving average so this simply counts how many candles are above the given moving average so we give a look back and a moving average and this little for loop will just count how many bars closed above this moving average over that look back period and then return that number same with bars below m a does the same thing just for bars below it bars crossed m a does the same thing as these two functions except that it checks how many times price action crossed the moving average so for example over this period here we had one two three four crosses over this period of price action here and so this function if i gave it let's say a 10 bar look back it would return how many times price action crossed above and below the moving average over that look back period this is useful for detecting potential periods of consolidation if price action has crossed the moving average too many times of your look back period then price is likely consolidating going sideways and then moving on we have our get pullback bar count so this counts how many green and red bars have printed recently ie our pullback bar count and by green and red i mean based on whatever direction you pass in so if you pass in one then this function will count how many green bars printed over our look back period if you pass in negative one it will count how many bearish or red bars printed over our look back period so this is useful for counting how many bars we've had pulled back against a certain direction so if we set our look back period to let's say 10 bars you can see that we've had one two three four five green bars over this period of price action and we do this just using a simple for loop that just loops our look back and it just checks if the closing price of that bar over our little historical look back for loop closed above or below it's open very simple function here i use this in the ultimate pullback indicator to count how many bars have pulled back since a new low because the rules of the pullback strategy require at least two green bars since price makes a new low and so i can use this function to verify that we have had a pullback now moving on we have a bunch of candle functions here this one gets the body size this one gets the top wick size so that's in pips how big the wick was on top of the bar so all of these are in pips get body size returns the current body size in points sorry not pips returns it in points you need to divide it by 10 to get pips on the forex market so we have get body size we have get top wick size we have get bottom wick size and get body percent so get body percent will return the candle body size as a percentage of the entire candle size so all of these functions are used for detecting certain candlestick patterns for example shooting star and hammer candles doji candles that sort of thing so for a doji candle i'd want to compare the top wick to the bottom wick to make sure they're of a similar size and then i'd want to compare the body percentage to the total size of the candle and if the body percentage of this candle is below a certain number usually i go with five percent so if this candle body is five percent or less of the entire candle size and both top and bottom wick are a similar size to each other then it's likely that we have a doji candle so that's what i use these for um moving on we then have our candle setup detection code so here we have our hammer detection so this function takes a couple of parameters here it takes the fib fib level and color match so color match simply means does the hammer need to be bullish green by default this is turned off so if you don't pass anything into this parameter then color match will be turned off and so a hammer could be red so an example of a red hammer would be this bar here it meets the criteria of a hema candle but it closed bearish it closed lower than it opened [Music] but it's still a sign of buying pressure same with the shooting star if color match is turned off which it is by default then this bar here would be considered a valid shooting star because it is still a sign of selling pressure due to the large wick and the tiny body which is below our fib level so if i open this up the default fib level is 382. um so what that means is the script is getting the fibonacci level of this bar and checking the 382 retracement so that's this red line here if the bar's body is contained below this number so it opened below this red line and close below this red line then we have a valid shooting star candle and same for hammer candles the candle must close above the 382 retracement so this would be an example of an invalid hammer candle because the bar open below our 382 enclosed above it we need both the open and the close to be above this number or this ratio this percentage of the candle size total size in order to be considered a valid hammer candle so that's what our hammer function does it just calculates our bull fib which is the 382 percentage mark of the total candle size then we check if the candle opened and closed above that level and then we check our color filter so if color color matches false which it is by default then this check will be ignored otherwise it will just check if the candle closed greater than opened and then it's the same thing for us shooting star candles exactly the same code except that we're checking our highest body closed above our fib level in order to be considered a valid shooting star moving on to the next candle which is a doji candle pattern which i just explained when we're going over the um get top width size get bottom width size and get body percentage i use all of those functions here to check the criteria of a doji candle so the first thing we do is make sure that the top and bottom wick size is within two times the size of the other wick so if we had a candle that looked like this um first of all you'd be asking yourself why you're using children's drawings to analyze price but if it did look like this this would not be a valid doji because the bottom wick is not within two times the size of the top wick the top wick is much larger than the bottom wick so this is more like a shooting star candle than a doji candle for doji candles we want this to be a sign of indecision so we want the candle to look more like this we want the body to be in the middle of the total candle size and the bottom wick and the top wick to be of a similar size this is a sign of stalling momentum or indecision in the market which can be a valuable entry pattern or an accurate entry pattern under certain market conditions especially if it's a swing high or swing low so this can make a great pullback entry pattern and a great counter trend pattern after price has exhausted itself so that's why i include that in my library i use this entry pattern in some of my scripts and that's what this code does it just checks those rules so we check the wix sizes and then we check our body percent is our candle body percent less than or equal to the given body size so by default the body size is set to 0.05 so you can call this function in your script without giving it any parameters and it will just use the default which is what i use in my scripts so default wick size of 2.0 and a default body size of 5 and that will return our doji candlestick patterns um this will return true if the current bar meets the rules of a doji then next up we have our bullish and bearish engulfing candle patterns so for these patterns we have a bunch of inputs to give the function the first is allowance point allowance so let me go to a market where i can demonstrate this issue and here is the example in question this candle here is a valid engulfing candle according to my discretionary rules i would count this as an engulfing cattle the problem is that the candle does not quite open below the previous candles close if you zoom right in enhance enhance enhance just print the damn thing you can see that it's one point off opening below or equal to the previous candles close so i included a parameter in this engulfing candle function called point allowance by default it's disabled it's set to zero but you can override this default by giving this value in the when you call this function so for example in the ultimate pullback indicator there is a setting down here under miscellaneous i believe yes point allowance if i set this to 1 and click ok now this candlestick pattern is being detected as a valid bullish engulfing candle because the point allowance is allowing for one point to be off so that is the purpose of point allowance this allowance parameter then we have rejection wick size this is just the rejection wick of the candle to the upside um so let me find an engulfing candle uh here's one here's a good example you can see that this candle here has a large rejection wick to the downside a bearish engulfing candle should be a sign that price momentum is shifting to the downside but if we have buying pressure here on the same candle that pushes price back up even though this engulfs the previous candle and is a swing high it could be argued this is a lower quality entry pattern because of the buying pressure we see here what we really want to see is a very small wick to the top or no wick at all like on this bar here which was a more reliable indication that price was becoming bullish now on most markets and time frames this check is is not necessary or this filter is not necessary because it doesn't really affect the win rate too much but i did find that on some markets and time frames having a rejection week too large to the downside like two times a body or greater is definitely not a good entry pattern and so i included an option here to set the maximum rejection width size now this is the maximum rejection week size compared to the body as a percentage so if you set this to 1 that would mean that a rejection width size of 100 percent of the candle body would be ignored so let me show you that in practice if i come down to my candle settings here max rejection width size is our rejection width setting if i set that to one this setup will go away there we go it's gone now because this rejection wick is greater than one times the size of the body and then finally we have engulf wick as a parameter so this just means the bar must engulf the previous candle's wick by default it's turned off um in this function but you can override this if you want to again that does affect the accuracy of this pattern on some markets some markets perform better if you make the bar engulf the wick so that's this setting here if i turn that on and turn this off you can see that our win rate has improved by a few percent just by making sure that the um candle engulfs the previous candles wick and that's it for our bullish and bearish engulfing candles apart from that we just checked the simple candlestick pattern does the candle engulf the previous candle and then we check our filters and obviously the same for bearish just in the opposite direction and so that's it for our candlestick patterns for now at least i'll probably add to these in the future but for now these are the candlestick patterns that this script detects moving on we now have our filter functions so we have a time filter here this just returns true if the current bar falls inside the specified session so this is used in a lot of my indicators to tell the script not to take setups during certain times of day and so i can use this time filter in this library across all of my scripts same with the date filter this just checks if the current bar's time falls within these two dates and then we have day filter this returns true if the current bar's day is equal to the given parameters so if you pass in true for monday and the current bar's day of week is equal to monday then this day filter will return true so this filter checks if the current bar's day is in the list of given days to analyze and then based on whichever day boolean you pass in true or false will tell the script should the script analyze this day so some scripts do not perform well on mondays for me some strategies and so i like to include a day filter in my scripts and having this as a library function is really cool because it just means i don't have to have all of this code this big block of code in all of my scripts i can just reference the library so moving on we have our atr filter so this function checks the current bar size against the given atr and the max size that you've specified so you can either pass in a custom atr value so for example maybe you want to check a 7 period rsi with your filter you can pass that in as your atr otherwise if you don't pass in anything the atr will be set to 1 1 1 1 by default and then over here the script checks if atr is 1 1 1 1 that means the user hasn't overwritten this atr value and so we just reference the standard 14 period atr otherwise we use the given atr to analyze the maximum size so the reason i did this i use this default value is so that you can simply call atr filter and then pass in a max size so for example atr 3.0 will return true if the current bar's size is less than three times the 14 period atr this is a useful filter for ignoring giant set up candles so sometimes the script will detect a setup candle that is just too big to trade for example this bearish bar here or this bearish bar here if these were valid entry patterns you wouldn't want to trade them because your stop loss and take profit are going to be massive compared to recent price action at least and so that's what i use the atr filter for and so this function just checks if the current bar's total size so the high minus the low is less than or equal to the atr value multiplied by our max size parameter and that's it for our filters now the final section in the script is our display functions i only have one function here at the moment and that is the fill cell function which just updates the given table cell with the given values so we pass in a table id we pass in the column and the row and then we can pass in a title a value a background color and a text color so you can see up here i have a table drawing onto the chart this script the upi script uses this custom function to update this table with the values you see there and so i put this function in the library because i like to display information on using tables in my scripts and so having this custom function here in the library just means less code that i need to put into all of my scripts anyway that is it for the zen library script i will be adding features and functionalities to the script in the future but for now this is the first version of the zen library or technically the second version because i did have to fix a bug with the time session filter this function here was doing the opposite it was determining if the current bar falls outside the specified session so i needed to fix that bug but technically this is the second version of the zen library but this is the first lesson i'm recording on the script and so any future updates any future versions i will record separate lessons on what i add to the script so i hope you found that interesting feel free to use this library in your own scripts or steal the code and do whatever you want with it and that's it i'll wrap this lesson up here and i will speak with you in the next lesson take care and good luck with your trading

Channel: The Art of Trading

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Keywords: tradingview, pine script, tradingview indicators, forex algo, crypto algo, stock algo, trading algo, trading algorithm, how to create trading strategies, how to code your own trading scripts, trading scripts, forex scripts, crypto scripts, stock scripts, bitcoin scripts, trading signals, forex signals, crypto signals, stock signals, detect trading setups, pine script mastery, pine script mastery course, how to use tradingview, how to use pine script, scripting, ema

Id: xFBvITwLoKg

Length: 36min 25sec (2185 seconds)

Published: Fri Nov 05 2021