python module naming convention underscorepython module naming convention underscore

Rust smart contracts? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. The other one is just a naming convention but I would guess this would say that you shouldn't import that file directly. 4 parallel LED's connected on a breadboard. How do I distinguish between chords going 'up' and chords going 'down' when writing a harmony? interface, the C/C++ module has a leading underscore (e.g. How can we compare expressive power between two Turing-complete languages? Modules should have short, all-lowercase names. rev2023.7.3.43523. How to take large amounts of money away from the party without causing player resentment? Python PEP 8 -- Style Guide for Python Code, Python Language Reference, section 3, "Data model". For example, Python module has such special variables: __name__ - this variable is equal to __main__ when script runs directly, and it is equal to module name when imported. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing, You are not expressly forbidden from inventing your own names. meanings. I wouldn't say that a prefixed underscore applies exclusively to C/C++ extension modules. Its Package and Module Names section only mentions such usage when a module is implemented in C/C++. To learn more, see our tips on writing great answers. dict, dir, doc, eq, format, ge. You also loose the additional log information that your commit modifies specific files (therefore involving specific classes). Is there an easier way to generate a multiplication table? Generating X ids on Y offline machines in a short time period without collision. x, _, y = (1, 2, 3) # Ignore the multiple values. Asking for help, clarification, or responding to other answers. Connect and share knowledge within a single location that is structured and easy to search. In this article I'll discuss the following five underscore patterns and naming conventions and how they affect the behavior of your Python programs: Single Leading Underscore: _var Single Trailing Underscore: var_ Double Leading Underscore: __var Double Leading and Trailing Underscore: __var__ Single Underscore: _ The current chosen answer already gave good explanation on the double-underscore notation for __init__.py. Its better to stick to regular imports for the sake of clarity. __double_leading_and_trailing_underscore__: "magic" objects or attributes that live in user-controlled namespaces. Is there a place that documents the use of leading. the build-in types is correct. Significance of double underscores in Python filename. Do large language models know what they are talking about? @StefanoBorini: PEP8 doesn't call for a single file approach. - Ram Rachum Apr 2, 2009 at 23:54 4 You observation w.r.t. also have short, all-lowercase names, although the use of underscores is Find centralized, trusted content and collaborate around the technologies you use most. Instead of being imported like this with its actual name: it is imported like this with a leading underscore: Now I know about most meanings of underscores in Python but I have not found anything that explains what a single underscore before the name of a module that we are importing is supposed to do. So you are saying that the module's name changes somewhere(like in a script in the project flow) and this is not some python related thing? How to maximize the monthly 1:1 meeting with my boss? Connect and share knowledge within a single location that is structured and easy to search. In this particular example, __init__.py defines the 'main' unit for a package; it also causes Python to treat the specific directory as a package. Connect and share knowledge within a single location that is structured and easy to search. I somewhat agree. Why are lights very bright in most passenger trains, especially at night? In the final act, how to drop clues without causing players to feel "cheated" they didn't find them sooner? mixedCase is allowed only in contexts where that's already the prevailing style (e.g. What is the purpose of installing cargo-contract and using it to create Ink! How to resolve the ambiguity in the Boy or Girl paradox? As you can see __baz got turned into _ExtendedTest__baz to prevent accidental modification: But the original _Test__baz is also still around: Double underscore name mangling is fully transparent to the programmer. In Python, the use of an underscore in a function name indicates that the function is intended for internal use and should not be called directly by users. It's just a convention but you should respect it. These are decidedly exceptions, though. Can we name python functions (not methods!) attributes, variables, camelCase only to conform to The only problem with using underscores is that you can't select a variable or function name with a double click you have to select the text manually. PI cutting 2/3 of stipend without notice. I've read some codes that used this way of creating parent-child classes. In general, that _single_leading_underscore notation is typically observed in function names, method names and member variables, to differentiate them from other normal methods. Does the DM need to declare a Natural 20? What's the correct convention of importing external packages? never get this completely consistent. Is there a non-combative term for the word "enemy"? What is the underscore prefix for python file name? I don't know how these people do research, my eye-tracking is definitely the fastest for short CamelCase and mixedCase names. How to resolve the ambiguity in the Boy or Girl paradox? What is the purpose of installing cargo-contract and using it to create Ink! It actually makes readability easier if you know that functions have underscores and classes don't. Underscores can be used in the module name if it improves readability. For example, youd pronounce baz as dunder baz. Its like a secret handshake for Python developers. Single and double underscores have a meaning in Python variable and method names. Lets take this list and look for our original variable names foo, _bar, and __bazI promise youll notice some interesting changes. Imagine you had the following code in a module called my_module: Now if you use a wildcard import to import all names from the module, Python will not import names with a leading underscore (unless the module defines an all list that overrides this behavior): NameError: name _internal_func is not defined. A user of course can make a custom special method, which is a very rare case, but often might modify some of the built-in special methods (e.g. How to maximize the monthly 1:1 meeting with my boss? list, string, etc. Note that the mangling rules are designed mostly to avoid accidents; it still is possible for a determined soul to access or modify a variable that is considered private. Python module that provides a higher level (e.g. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Personally, I like to use snake_case for the internal, low-level, system stuff, and keep mixedCase / CamelCase for the interfaces. The self.foo variable appears unmodified as foo in the attribute list. Thanks for contributing an answer to Stack Overflow! Why did only Pinchas (knew how to) respond? Is there an accepted naming convention for such internal modules? Scottish idiom for people talking too much. It does this to protect the variable from getting overridden in subclasses. This demonstrated that name mangling isnt tied to class attributes specifically. Most python operators have an associated "magic" method (for example, a[x] is the usual way of invoking a.__getitem__(x)). Why are Python's 'private' methods not actually private? How can we compare expressive power between two Turing-complete languages? Short answer: use a single leading underscore unless you have a really compelling reason to do otherwise (and even then think twice). further to what @JohnTESlade has answered. from M import * does not import objects whose name starts with an underscore. It is the unit that will be used when you call import cherryPy (and cherryPy is a directory). rev2023.7.3.43523. In cherryPy for example, there are files like: How are they different? However, leading underscores do impact how names get imported from modules. Should I disclose my academic dishonesty on grad applications? Tkinter.Toplevel(master, class_='ClassName'). rev2023.7.3.43523. Avoid this naming scheme for your own attributes. How can we compare expressive power between two Turing-complete languages? Personally I try to use CamelCase for classes, mixedCase methods and functions. I know this sounds rather abstract. Though, I admit that some of the answers there cover this case as well. "What is the historical reason why Python uses the double underscore for Class Private members?". Any recommendation? Not as far as I know, but there are some things seen often: Thanks for contributing an answer to Stack Overflow! Moreover, another PEP-8 guideline states: single_trailing_underscore_: used by convention to avoid conflicts with Python keyword, e.g. Find centralized, trusted content and collaborate around the technologies you use most. Why did CJ Roberts apply the Fourteenth Amendment to Harvard, a private school? Never mix tabs and spaces. Perhaps surprisingly, name mangling is not applied if a name starts and ends with double underscores. Does "discord" mean disagreement as the name of an application for online conversation? 1 @MackM Note that this question asks about underscores before and after the name, and the duplicate target that you proposed asks about underscores only before the name. I find it difficult to browse, despite folding. Naming convention indicating a name is meant for internal use. Looking for advice repairing granite stair tiles. What are the requirements for naming python modules? In the Python standard library, a leading underscore in a module name may denote an accelerator module: a module written in C that provides a more performant implementation of the pure Python version, for example _csv and csv. From the Python PEP 8 -- Style Guide for Python Code: The following special forms using leading or trailing underscores are There is few need (if any at all), to use _single_leading_underscore.py on filename, because the developers are not scrapers , they are unlikely to salvage a file based on its filename. underscore naming convention in Python 2019-03-26 Eric Computing Naming convention, Python, Underscore Single and double underscores have a meaning in Python variable and method names. I understand your point but in the case of private attributes in a class, wouldn't be better to use a double underscore? Thus following the Zen of Python's "explicit is better than implicit" and "Readability counts". Underscores can be used I have seen this naming convention for variables but I am not sure it is a good practice to name modules like this). Class name in python should follow naming scheme called CapWords convention. rev2023.7.3.43523. gt, hash, init, le, lt, module. Raymond also explains why you'd want the name mangling behavior starting at around 34 minutes into this video: So the choice between the single leading underscore and double leading underscore in a name is a bit like choosing between protected and private in C++ and Java? "nibmodule"? Understanding practical usage of __ (double underscore) in python, What is the meaning of simply __ double underscore as a variable name Just __ not follow another chars, function parameter names starting with underscore, PYTHON: double-underscore prefixed parameter in *function*. Should i refrigerate or freeze unopened canned food items? When should I use underscores between words in Python function names (according to the style guide)? your here-link is dead, maybe it should be replaced by something like. Does "discord" mean disagreement as the name of an application for online conversation? answered Apr 2, 2009 at 22:34 Stephan202 59.7k 13 127 132 3 Do most Python projects follow this convention? PI cutting 2/3 of stipend without notice. What is the underscore prefix for python file name? magic functions). Method Naming. @AreTor what's important is to clearly mark what's public and what's not - not to make attributes "private". To subscribe to this RSS feed, copy and paste this URL into your RSS reader. In the case of one underscore, the underscore prevents the from X import * statement to import this kind of variables. What should be chosen as country of visit if I take travel insurance for Asian Countries. Why is it better to control a vertical/horizontal than diagonal? This rule covers things like init for object constructors, or call to make an object callable. PEP 8, sometimes spelled PEP8 or PEP-8, is a document that provides guidelines and best practices on how to write Python code. Is nested function a good approach when required by only one function? Import __module__ python: why the underscores? Also: The result of the last expression in a Python REPL. This is the name mangling that the Python interpreter applies. How do you manage your own comments on a foreign codebase? Take a look at the following example that will confirm this: AttributeError: ManglingTest object has no attribute __mangled'. Not the answer you're looking for? rev2023.7.3.43523. As for me - camelCase or their variants should become standard for any language. E.g. Packages for an explanation of how to create modules. Does this change how I list it on my CV? Plot multiple lines along with converging dotted line. 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. 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. What are the requirements for naming python modules? If youre wondering Whats the meaning of single and double underscores in Python variable and method names? Ill do my best to get you the answer here. Three months ago, he was laid off from Twitter. Java's or C#'s (clear and well-established) naming conventions for variables and functions when crossing over to Python. It is generally not enforced by the Python interpreter and meant as a hint to the programmer only. I like using _ for variables, but from eyes, it just looks a little funny to me for functions and methods. Is the difference between additive groups and multiplicative groups just a matter of notation? These methods provides special syntactic features or do special things. This leads to imports like the following: It's a bit like emulating the Java way. Naming conventions for function arguments in python, Python naming convention for variables that are functions. Triggers name mangling when used in a class context. Why do some functions have underscores "__" before and after the function name? Why did CJ Roberts apply the Fourteenth Amendment to Harvard, a private school? When does the name mangling occur when using double underscores? My question now is: why not use two underscores only? I do understand the reason behind the python style, but I am not too fond of having a very large file containing a lot of classes. Thank you. This may have been true in '08 when this was answered, but nowadays almost all major libraries use PEP 8 naming conventions. This can potentially lead to a higher quantity of conflicts to be resolved. And not all _-prefixed modules are even implemented in C! They're listed in the Python Language Reference, section 3, "Data model". That's the thing, I am a bit confused because I haven't seen a module named like this (underscore at the end) in any project till now, despite being said that "Modules can contain underscores". Does underscore character in python variable names matter to the interpreter? Keeping in mind, of course, that it is best to abide with whatever the prevailing style for a codebase / project / team happens to be. Do most Python projects follow this convention? private to this class on instances of other classes. Maximum Line Length Limit all lines to a maximum of 79 characters. names be chosen to be fairly short -- this won't be a problem on Unix, When to use protected and private attributes? Any recommendation? Yes, a package or module needs to have a valid Python name. 586), Starting the Prompt Design Site: A New Home in our Stack Exchange Neighborhood, Testing native, sponsored banner ads on Stack Overflow (starting July 6), Temporary policy: Generative AI (e.g., ChatGPT) is banned, python: naming a module that has a two-word name, Python Naming Conventions for Dictionaries/Maps/Hashes. There is PEP 8, as other answers show, but PEP 8 is only the styleguide for the standard library, and it's only taken as gospel therein. Connect and share knowledge within a single location that is structured and easy to search. _socket). Class name in Python. If you encounter them in the wild one day, youll know what to look for in the documentation. Rust smart contracts? Used by convention to avoid naming conflicts with Python keywords. getattribute, gt, hash, init, le. Use an underscore to join multiple words to generate a meaningful module name. Is Linux swap still needed with Ubuntu 22.04. TL;DR It says that snake_case is more readable than camelCase. single_trailing_underscore_: used by convention to avoid conflicts with Python keyword, e.g. Are there good reasons to minimize the number of keywords in a language? What does the Python naming convention with single/double underscore before a function mean? that are denoted by capital letters. Wait, why did we get that AttributeError when we tried to inspect the value of t2.__baz? Not the answer you're looking for? However, that is the naming convention for C/C++ modules according to PEP8. How do laws against computer intrusion handle the modern situation of devices routinely being under the de facto control of non-owners? list, string, etc. Ok I think I have understood the use of one and two heading underscores in Python. And I believe there is no real need for _cptools.py notation in a filename. with leading underscores? Do large language models know what they are talking about? Feel free to dismiss me as a heretic. I hate it when people associate the single leading, When to use one or two underscore in Python [duplicate]. How can we compare expressive power between two Turing-complete languages? I have searched around for this but I did not find any answer. Typically, one follow the conventions used in the language's standard library. Using the same name for variables which are in different functions? nib is fine. rev2023.7.3.43523. As an example I can provide this code: This convention is used for special variables or methods (so-called magic method) such as __init__ and __len__. I prefer using lower_case_with_underscores for variables and mixedCase for methods and functions makes the code more explicit and readable. Equivalent idiom for "When it rains in [a place], it drips in [another place]". E.g. Are there good reasons to minimize the number of keywords in a language? Developers use AI tools, they just dont trust them (Ep. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. I, personally, prefer this one for it's shortness and because everyone knows what it means. Should I be concerned about the structural integrity of this 100-year-old garage? There is also a convention that a name starting with an underscore is internal and should not be used by clients. What does the underscore represent in Python? Enforced by the Python interpreter. Not the answer you're looking for? David Goodger (in "Code Like a Pythonista" here) describes the PEP 8 recommendations as follows: joined_lower for functions, methods, As the Style Guide for Python Code admits, The naming conventions of Python's Python shared object module naming convention. Scottish idiom for people talking too much. What does skinner mean in the context of Blade Runner 2049, Comic about an AI that equips its robot soldiers with spears and swords. In the implementation of the standard library in CPython, the _ prefix seems to indicate that a module is "private", in the sense that you shouldn't import it directly. What should be chosen as country of visit if I take travel insurance for Asian Countries. This excludes names with hyphens in it. 586), Starting the Prompt Design Site: A New Home in our Stack Exchange Neighborhood, Testing native, sponsored banner ads on Stack Overflow (starting July 6), Temporary policy: Generative AI (e.g., ChatGPT) is banned. What are some examples of open sets that are NOT neighborhoods? One class per file is detrimental to the code structure. Book about a boy on a colony planet who flees the male-only village he was raised in and meets a girl who arrived in a scout ship, Plot multiple lines along with converging dotted line. Is Linux swap still needed with Ubuntu 22.04. Interestingly, it also says, "The results of this study might not necessarily apply to identifiers embedded in source code. b) Unattractive mixture of CamelCase and underscores? How do I concatenate two lists in Python? These are decidedly exceptions, though. Does Python have a string 'contains' substring method? I'm looking at a Python code written by someone else and there is a module say "GUI_Module". Modules should have short, all-lowercase names. Lets find out: You just saw that the leading single underscore in _bar did not prevent us from reaching into the class and accessing the value of that variable. Do large language models know what they are talking about? Prepending a single underscore (_) has some support for protecting module variables and functions (not included with import * from). ctypes vs _ctypes - why does the latter exist? One class per module and one file per (code unit) are two extremes of a very wide spectrum. Use. PI cutting 2/3 of stipend without notice. Can module names in Python end with an underscore? You shouldn't invent your own names using the double-underscore notation; and if you use existing, they have special functionality. Another reason is version control: having a large file means that your commits tend to concentrate on that file. That way I can easily know how to name my new functions/methods: Camel case starts with a lowercase letter IIRC like "camelCase". 586), Starting the Prompt Design Site: A New Home in our Stack Exchange Neighborhood, Testing native, sponsored banner ads on Stack Overflow (starting July 6), Temporary policy: Generative AI (e.g., ChatGPT) is banned, VS Code python doesn't autocomplete scipy.stats. What is the meaning of single and double underscore before an object name? Python: Naming conventions for modules & variables when they could conflict, Changing non-standard date timestamp format in CSV using awk/sed. Ive been using Python for years but rules and special cases like that arent constantly on my mind. To me, they provide better way to make attributes private, rather then one underscore attributes. Developers use AI tools, they just dont trust them (Ep. Your preference was my initial intuition coming from a lot of years of Java development. Asking for help, clarification, or responding to other answers. Never invent such names; only use them as documented. Should I disclose my academic dishonesty on grad applications? E.g. If they can't get that consistent, then there hardly is much hope of having a generally-adhered-to convention for all Python code, is there? Most of the times if your base class needs a distinct namespace for a set of implementation attributes (and methods using them) then this is better delegated to another object. rev2023.7.3.43523. Variable names follow the same convention as function names. What conjunctive function does "ruat caelum" have in "Fiat justitia, ruat caelum"? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, The future of collective knowledge sharing. The only thing that seems to be universally true of these _-prefixed modules is that they're all implementation details of some documented, "public" module that doesn't have a _-prefix, and that you're supposed to use that module instead of directly importing stuff from the _-prefixed one. Not the answer you're looking for? For example, the PEP mentions "CamelCase" while you mention "camelCase". 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. Find centralized, trusted content and collaborate around the technologies you use most. Whats going to happen if you instantiate this class and try to access the foo and _bar attributes defined in its init constructor? Variables surrounded by a double underscore prefix and postfix are left unscathed by the Python interpeter: However, names that have both leading and trailing double underscores are reserved for special use in the language.