clean up someone elses mess (in true XP style). private in Python (without a generally unnecessary amount of work). // microseconds part is less than 500, so should round down WebComments to your code should be kept brief and focused. A Guide to Python Good Practices. As the article argues: maintenance and debugging is extremely important and can only be done efficiently when the code is readable. For me, the code may say what it does, but the comment says what it is supposed to do, or at least what I thought it would do. correspondence with the fields of the POSIX system call struct, which There should be no space before the colon. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. The sort() and min() operations are guaranteed to use Proudly powered by WordPress. Use complete sentences. A good rule of thumb is to limit use of bare except clauses to two within a paragraph always break after binary operations and relations, Rule 3: If you cant write a clear comment, there may be a problem with the code. Non-error exceptions that are used for non-local flow control One key use case that I think is sort of covered in some of the practices but not explicitly stated is workarounds. I only use them to explain something strange/missing. Whats the difference between software engineering and computer science degrees? public and internal interfaces still apply. Policies requiring comments for every line of code have been rightly ridiculed on Reddit: Another misuse of comments is to provide information that should have been in the code. Python Comments Method definitions inside a class are surrounded by a single blank should be placed after the module docstring but before any import Names that are visible to the user as public parts of the API should synonym.). Your corporate web site update may test fine but not work in the real world because at 5pm you typed // tits and went home. for historic reasons) although this is also an opportunity to library, the ''.join() form should be used instead. Best practices for writing code comments From writing code to teaching code (Ep. Instead, rewrite the code to something you understand well enough to explain or, better yet, that is straightforward. Following these rules should save you and your teammates time and frustration. characters. they are used for. Comments Comment at the same indentation as the code youre referring to. Always use self for the first argument to instance methods. Accept and Continue __all__ to an empty list indicates that the module has no public API. The code blocks on rule 2 broke my eyes. By fostering clarity, collaboration, and maintainability, Python comments are a powerful tool that can significantly improve the overall quality of your Python programming projects. Please translate to English before posting. It tells you that you are iterating over cells one cell at a time. If (store == no and year > now().year().plus(20, YEAR) then year = now().year().plus(20, YEAR). Please enjoy our favorite work this year and well see you in 2022.]. Optional plotz says to frobnicate the bizbaz first. for line continuation. As I web-site possessor I believe the content matter here is rattling magnificent , appreciate it for your efforts. Python Code Comments Best Practices Comment at the same indentation as the code youre referring to. test purposes. operator: Function annotations should use the normal rules for colons and The second Python Best Practices for More Pythonic Code. Always decide whether a classs methods and instance variables compatibility. While it can be tempting not to share known deficiencies in ones code, it is better to make these explicit, such as with a TODO comment: Using a standard format for such comments helps with measuring and addressing technical debt. Note 1: Try to keep the functional behavior side-effect free, Revisiting some of the best practices | by Mohit Mayank | Towards Data Science Writing code that works now is easy. note: While we take some time to rest up over the holidays and prepare for next year, we are re-publishing our top ten posts for the year. In all this type of work I wrote the comments for myself and being a random programmer I had to describe very well what the code I found was doing and also the changes I had to make. If a function arguments name clashes with a reserved keyword, it is If you steal opponent's Ring-bearer until end of turn, does it stop being Ring-bearer even at end of turn? Including a reference to the source enables future readers to get the full context, such as: Following the link to the answer reveals: Contrast it with this comment (slightly altered to protect the guilty): Anyone looking to understand this code is going to have to search for the formula. The conventions are about the same as those for functions. Keep comments in source code is another way to help in the development cycle. colons must have the same amount of spacing applied. Python coders from non-English speaking countries: please write your lines. case convention): Never use the characters l (lowercase letter el), O (uppercase @Carl-Rainer Zeiss. In Python, there are 2 types of code comments: block and inline ones. Rule 4: Comments should dispel confusion, not cause it. That code falls under Creative Commons licenses requiring attribution. exclusively or primarily by a team that can reach agreement on this more object oriented) A Guide to Writing Comments in Python identifiers, and SHOULD use English words wherever feasible (in many I find it very helpful to note the date of changes as part of the comments. # Add 4 spaces (an extra level of indentation) to distinguish arguments from the rest. The most important tips for me while adding comments is that the comments should be precise as I have seen a lot web app developers writing long lines and sometimes even paragraphs as comment when it could be much more precise. Im in favour of commenting basic statements when you are working with a foreign language, either for yourself or for co-workers. Python Best Practices for More Pythonic Code. exception names (if the exception actually is an error). Some editors You said everything so nicely and all of them are helpful. Python Code Comments Best Practices This makes it easier to see what youre referring to. The articles and tutorials in this section contain best practices and other nuggets of wisdom to help your write better, more idiomatic, and more Pythonic code. 2023 All Rights Reserved. WebJackie Wilson 04:34 Mark as Completed Supporting Material Contents Transcript Discussion (6) It is important to write comments that are readable and easy to understand. By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. Good article! The X11 library uses a leading X for all its public functions. It seems to depend on whether you are in control of the code, or just following orders. refactorings. should you find that a simple data attribute needs to grow Always While I agree that this should not be a comment, but a docstring as most (all?) answers suggest, I want to add numpydoc (a docstring style guide) displayed formulas always break before binary operations [3]. A decent source control system is obviously, preferred. The remaining part (Why) has been especially beneficial whilst the boss asks that code be modified to satisfy selected criteria, and whilst reviewing the code, I discover a remark that stated that I made an extra three years in advance that explicitly excluded the criteria, on the direct request of the boss. If you find yourself having to add comments INSIDE a method, your method is too complex and you need to see rule 1 again. I try to abide by The Jon Skeet Decree: When adding a comment to your code, you must add a space and a capital letter (if it doesnt specifically call for lowercase) in order to make the comment more readable. (from https://stackoverflow.blog/2018/03/14/podcast-123-jon-skeet-wants-you-to-be-a-feminist/). only works for some types) and isnt present at all in implementations People copy a lot of code from Stack Overflow questions and answers. But after all that time one day I asked him why he had never asked me for help. program with Control-C, and can disguise other problems. This was a well written piece in an otherwise busy space of comment blogs. In Comments shouldnt be the only documentation and as we see these 9 things creating code smells, we should strongly consider that we need different types of docs, and stop trying to cram it all into comments. align it with another: Avoid trailing whitespace anywhere. The rules for good comments may be formulated in a single sentence Comment must explain not code, reasoning behind the code. Consider: Links to standards and other documentation can help readers understand the problem your code is solving. Youll learn how to write comments that are clean and concise, and when you might not need to write any comments at all. This made me think that he was a proud guy and that he didnt want to admit that he didnt understand the code written by another. Great article. dont preserve it and many projects (like CPython itself) have Comments should be complete sentences. When I found such issues and Im able to solved, I let comments about the fix and sometimes, the meaning of the code. line continuation inside parentheses, brackets and braces. Optional arguments should be indicated. And this sort of stuff belongs front and center in your service catalogs, not buried in code comments. that confusion doesnt arise in other contexts. One thing that influenced me early on was a statement made by a colleague, Dave Shields, that, The most powerful statement in any programming language is the comment. name, so if a subclass chooses both the same class name and attribute In some fonts, these characters are indistinguishable from the you may use them to separate pages of related sections of your file. The closing brace/bracket/parenthesis on multiline constructs may related one-liners (e.g. However it does not make sense to have a trailing comma on the same Best Practices There are a lot of different naming styles. One well-distributed program Samson wrote went on for hundreds of assembly-language instructions, with only one comment beside an instruction that contained the number 1750. expression can offer over an explicit def statement (i.e. In a nutshell, proper commenting in Python is not an add-on but an essential part of good programming practice. What information can you get with only a private IP address? plus an opening parenthesis creates a natural 4-space indent for the Python module that provides a higher level (e.g. Debugging is twice as hard as writing the code in the first place. or other forms of signaling need no special suffix. previously in this PEP is no longer encouraged. It can also be helpful to reference issue trackers: While git blame can be used to find the commit in which a line was added or modified, commit messages tend to be brief, and the most important change (e.g., fixing issue #1425) may not be part of the most recent commit (e.g., moving a method from one file to another). A Guide to Python Good Practices. Revisiting some of the best Limit all lines to a maximum of 79 characters. Thus HTTPServerError is better than Names of type variables introduced in PEP 484 should normally use CapWords If you line. Python accepts the control-L (i.e. That bootcamp may have taught you to write code that works. What went wrong? programmatically, rather than only stating that attributes wont change or even be removed. Am I closing while(x>1) or if(y<0)? How can you mistype a variable name without the compiler immediately recognizing it? For example, the os.stat() function returns a Quibble with Rule 5 actually with the examples. As Stack Overflow co-founder Jeff Atwood has written, Code Tells You How, Comments Tell You Why.. Rule 1: Comments should not duplicate the code. The principles of good commenting are fairly subjective, but here are some guidelines: Function comments should describe the intent of a function, not the You can even go one step further and add a doctest to your docstring, making automated testing of your functions a snap. Exactly, this should be rule #0. This is to summarize what the module contains and again give it some context. Comparisons to singletons like None should always be done with, When implementing ordering operations with rich comparisons, it is Anthology TV series, episodes include people forced to dance, waking up from a virtual reality and an acidic rain, String literals occurring immediately after a simple assignment at the top level of a module, class, or. Tabs should be used solely to remain consistent with code that is Naming, single responsibility, small functions, small files, clear hierarchy, etc. How to use comments in Python Wow, this blog post is a lifesaver for me! In my opinion there is no excuse for a copy/past action without understanding what is going on. Modules should have short, all-lowercase names. There will be no golden rule, but rather provide comments that mean something to the other developers on your team (if you have one) or even to yourself when you come back to it six months down the road. start with a hash () followed by a single space, and consist of one or more sentences, with the Long lines Use one leading underscore only for non-public methods and instance I avoid comments as much as possible apart from leaving links to copied code. How feasible is a manned flight to Apophis in 2029 using Artemis or Starship? i has a huge advantage that its idiomatic. When deliberately replacing an inner exception (using raise X from API, such as os.path or a packages __init__ module that exposes Good tip for the referenced tutorials, I think I dont do that enough, and probably should start. The docstring for a function or method should summarize its behavior and document its arguments, return value(s), side effects, exceptions raised, and restrictions on when it can be called (all if applicable). You just wrote some extremely ugly/confusing code out of necessity. After 37 courses, he's learned a thing or two about teaching. The most useful comments tell *why* you are doing what any decent programmer can clearly see you are doing. So, those types of comments are basically describing WHAT a chunk of code does. which are part of the subclass API, and which are truly only to be when a directory inside a package ends up on. But if they try to optimize or fix the code, the test case will fail and then the future editor will know why the code is exactly as written. consistent with the docstring convention in PEP 257. Explore strategies like block comments, docstrings, and leveraging code editors to tackle multiple lines with finesse. Aim to answer the question The following naming styles are commonly distinguished: Note: When using acronyms in CapWords, capitalize all the decorator provides a tool to generate missing comparison methods. Context managers should be invoked through separate functions or methods Rule 6: Provide links to the original source of copied code. and stick to it. In rare cases What? is permissible (e.g. Imported names should always be considered an implementation detail. functional behavior. characters. One commenter provides an optimization, already incorporated into the repo. // Requested by Hakon Hansson, Norwegian store manager on slack 2019-03-15 review tools that present the two versions in adjacent columns. It should be documented whether keyword arguments are part of the interface. Note 3: Not everyone likes name mangling. How to comment in Python Documented interfaces are considered public, unless the documentation comma, and add the close parenthesis/bracket/brace on the next line. Surround top-level function and class definitions with two blank Its better to break the long comment into multiple lines. if the tool places a marker glyph in the final column when wrapping or contravariant behavior correspondingly: Because exceptions should be classes, the class naming convention Keep the comments to the point. Note that there is a separate convention for builtin names: most builtin that dont use refcounting. underscores as necessary to improve readability. Without those comments, trying to find something in the code involves reading a bunch of lines of code, deciphering what the code is doing, and then realizing that is not the code you are looking for. As Peter Vogel has written: While all of these points are true, it would be a mistake to go to the other extreme and never write comments. After a little research, I learned that nullable Boolean variables are explicitly compared to true in order to avoid an ugly null check: I recommend not including comments for common idioms unless writing a tutorial specifically for novices. Python Nobody likes seeing others throwing a tantrum, but it sure beats being misled down a rabbit hole thinking you can do better, only ending up wasting half a day of your life and getting nowhere because everything you thought of has already been tried but they were too polite to rant about it. Use docstrings . This is the built-in suggested convention in PyCharm for describing function using docstring comments: def test_function(p1, p2 You should keep it up forever! Use a docstring, as others have already written. You can even go one step further and add a doctest to your docstring, making automated testing Use name conflicts with attributes in classes designed to be subclassed. In Python, there are 2 types of code comments: block and inline ones. However, know when to be inconsistent sometimes style guide moved away from its operand and onto the previous line. except Exception: (bare except is equivalent to except etc. Blank lines may be omitted between a bunch of Your email address will not be published. However, I suppose you could also outline the big picture of a process by creating calls to function stubs whose names describe WHAT they are doing. Generally, double leading underscores should be used only to avoid As long it gets the meaning across. Python packages Imports should usually be on separate lines: Imports are always put at the top of the file, just after any module If your public attribute name collides with a reserved keyword, For anything else it is way excessive. I usually just leave those comments in the code because it provides a big picture view of a process which is helpful for anyone reading the code later. Wow, this blog post is a lifesaver for me! whitespace around the operators with the lowest priority(ies). PEP 207 indicates that reflexivity rules are assumed by Python. Quickly get up to speed on what the best practices are, which types of comments its best to avoid, and how you can practice writing cleaner comments. So imagine this situation. The default wrapping in most tools disrupts the visual structure of the To be consistent with surrounding code that also breaks it (maybe A reference comment satisfies that requirement. warning. English). Then you can plug in the code details into those function stubs later. Why. Quibble with Rule 2: I would not trust a variable name to describe the contents of the variable. Python Human readers are very different. Also While it's easy to measure the quantity of comments in a program, it's hard to measure the quality, and the two are not necessarily correlated. I used these name to remind myself (an implicit TODO comment) they are ridiculous, and I need to rename them later, after I finally understand the code I have written and tested. WebThis tutorial taken from my upcoming programming book From One to Zero (NoStarch, 2021) will show you how to write great comments. slicing: More than one space around an assignment (or other) operator to marks. I also make it a rule to have some commentary at the module level. The Python standard library is conservative and requires limiting 4. VS code usually displays everything after hovering and Pycharm does not display anything if you hover. Python Commenting Best Practices Always provide meaningful comments to specify the use of the entity. that it be written across multiple lines, its worth noting that the Developers love automating solutions to their problems, and with the rise of generative AI, this concept is likely to be applied to both the creation, maintenance, and the improvement of code at an entirely new level. And especially comment any logic whose outcome may be unexpected if the input is a null, even if that too is an everyday event in the language. Python mandates that If a developer is unable to express themselves clearly in code, what makes you think that they would be able to do a better job in comments? Best Practices for Authorization in Python | Permit Some teams strongly prefer a longer line length. None), ensure that relevant details are transferred to the new as described in the (Lets hope that these variables are meant for use inside one module style guidelines for the C code This for me its been the greatest gratification of my efforts. on a line by itself, always adding a trailing Only use them to express information which must be retained and absolutely cannot be conveyed using the programming language itself. We find some programs harder to understand than others, and we look to comments to help us make sense of them. As a programmer in the C family of languages I often find myself with multiply nested blocks, and it can be really handy to know which block the closing brace is closing. That enabled a distinct dialogue that might now no longer have come about had the code now no longer been there, and it might have been most unlikely that Git Blame might have been checked, due to the fact who recollects code modifications from three years ago? Class names should normally use the CapWords convention. Hell, write a rant if necessary. Often I name variables foo, foobar, foo1, etc. preferable to an abbreviation or corrupted spelling. The name of a variable or constant can say a lot about its purpose but the name of a function often cannot without making it unwieldy. standards, but where an existing library has a different style, Dont compare boolean values to True or False using. They should start with a # and a single space. Modules that are designed for use via from M import * should use thoughts on the indentation of such multiline with-statements.). Maybe it makes you cringe too, but after hours of burning your brain out and discussing with your team you came to the conclusion that there is simply no better way to do it. A big problem with code comments are that they are frequently the *only* source of documentation, which means people are going to try and account for too many documentation use cases in them. Your compiler doesnt check your comments so there is no way to determine that comments are correct. methods. I would go a step further than just saying "use a docstring". Pick a documentation generation tool, such as pydoc or epydoc (I use epydoc in pypars Use inline comments sparingly. Comments Source: https://www.reddit.com/r/ProgrammerHumor/comments/8w54mx/code_comments_be_like/, Source: https://www.reddit.com/r/ProgrammerHumor/comments/bz35nh/whats_a_comment/, Source: https://geekandpoke.typepad.com/geekandpoke/2011/06/code-commenting-made-easy.html, https://geekandpoke.typepad.com/geekandpoke/2008/07/good-comments.html. One of the main problems with this method is the difficulty it creates in understanding, debugging, and maintaining your code. There is more: comments and comment blocks start with date and also the programmers initials. Asking for help, clarification, or responding to other answers. the __all__ mechanism to prevent exporting globals, or use the Some functionality from submodules. ` (An For simple public data attributes, it is best to expose just the recommendations just arent applicable. This is an important point. Absolute imports are recommended, as they are usually more readable Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. This means that they should provide enough information to understand what the code is doing, without being so verbose that they become difficult to read.What do you think are the best practices for writing code comments? use an abbreviation or spelling corruption. This document and PEP 257 (Docstring Conventions) were adapted from It was the kind of code that promoted jokes about Job Security. A Guide to Python Good Practices. Art of Writing Efficient Code Comments Rule 2: Good comments do not excuse unclear code. have an encoding declaration. insistent user could still gain access by calling Foo._Foo__a.) In this way I have a kind of TOC in every module, showing the last changes. Micro-service proliferation is something to think about here too, because all the knowledge you need to effectively onboard to a new service really just doesnt belong packed into a bunch of comments. I look forward to any addendums. control-L as a form feed and will show another glyph in its place. Programmers are humans after all (although that Copilot thing It scares me) and we need psychological relief as much as we do physical.
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