Code Formatting In Python With Black - Python Tutorial

Key Takeaways

do you think this is the best way to format your python code or this or maybe even this what's up everyone if you're new to the channel i'm patrick and i do weekly videos on python and machine learning related topics and if you follow my tutorials then you should know that i do care about code formatting and having a nice and clean code so why did i say in the title that i don't care and the reason is i don't care about code formatting while i'm writing code instead i use a tool that is doing this automatically for me so i can save time and energy and focus on the more important things so in this video i want to show you this tool and maybe i convince you to use this tool as well it's actually pretty simple so the tool i'm using is called black and you can find it on github and it tells us it's the uncompromising python code formatter and it's actually in the repo of the official python software foundation so even they recommend to use this and if you have a look at the readme then it tells us it's the uncompromising python code formatter by using it you agree to see control over minutiae of hand formatting i actually had to google it so it means we see control over details of our code formatting and in return black gives you speed determinism and freedom from pi code style nagging about formatting you will save time and mental energy for more important matters so no longer discussing or fighting with your colleagues what's the best code style instead you just run this code and there are no compromises and then you have a nice formatted code and i actually like this code format that black is enforcing and if we scroll down to the used by section then we can see that black is used in a lot of open source projects and also by the following organizations like facebook dropbox mozilla and quora so a lot of people trust this tool and so do i now in order to install and use this we just have to say pip install black and then to use it we can say black and then we can either use a single python file or a whole directory and then it's formatting the whole directory and there is a list of command line options but actually the only one that lets you configure and change the code style is the minus minus line length command with this you can change the characters per line to allow so that default is 88 and this is actually the only thing that you can change and configure that affects the code styling and everything else is fixed and no compromises here so here i'm in my editor and i prepared an example file that i want to edit with black in a second so you can see i have a function then i have a list where i didn't know where i should start a new line and the same with a dictionary and then we have this function from the beginning and now here you can see some parts of the code are already underlined so here my editor pycharm is already clever enough to detect these minor issues so if i hover over this with the mouse then you should see the hint it expected two blank lines found zero after the importing and also here for the comment if i hover over this then we see at least two spaces before inline comment and then also at the very end we have a small underline here so if i hover over this then we see no new line at the end of the file so according to the python style guide you should always end your file with a new line so these are all minor issues with my code formatting but i actually don't care about them while i'm writing the code instead afterwards i use my terminal and here i already said pip install black and then i say black and then the file name so in this case it's called example.pi and now i will run this and then notice what happens to the file alright so the formatting happens in the terminal we can see all done one file reformatted so now let's have a look so here you can see that after the import statement we have two blank lines then we have our function then again we have two blank lines then for this list it detected that this is short enough to be put into one single line but not for this dictionary here for this it used separate lines and also for this function it used a separate line for each argument and then we have at the very end we can also see that we have a new blank line at the end so now all is good and we don't have anything underlined as well in pycharm so yeah this is actually everything you need so you don't have to care about the code formatting and then just run black and your file name or the whole directory and you're good to go so i want to mention one more thing in our code you see that the logging is unused that's why it's appearing slightly more dark and also for this function argument this is not used but black does not remove the unused code so this is not what black is doing it's not changing your code it's only changing the code formatting so this is very important and i wanted to make this clear here and now i want to show you one more trick so you don't even have to run black yourself you can automate this as well so if we go back to the readme of black and scroll down there we can find the section version control integration so if you use git in your project then you can use this pre commit hook so you just install this and then you put this in a file that is called dot pre-commit config.yml and you put this in your repository and then you write these commands here and then what happens is whenever you commit your changes it will automatically apply black to all the files and then you have a nice code formatting without even running it manually so this is pretty cool and then when you upload it to github then you have a nice formatted code so you can use this as a pre-commit hook and this is actually what i recommend then you can see the changes already locally before pushing it but you can also run this as a github action for example you can define this for each push or pull request and then it's running black automatically for you whenever you push or make a pull request so yeah i recommend to try it out see if you like it and if you can save some time with it and yeah i hope you enjoyed this tutorial and then i hope to see you in the next video bye you