在 Python 中将类或方法命名为“类”的约定是什么？

Question

Let's say I have a class in Python like this:

class Student:
    def __init__(self, classs):
        self.classs = classs

Now, what's convention for naming a parameter (and class property) classs ? I saw classs as well as klass and I'm wondering: is there some convention for it? Didn't find it in PEP8.

Answer 1

PEP 8 advises to use a trailing underscore in that case: class_ .

See https://www.python.org/dev/peps/pep-0008/#descriptive-naming-styles for details:

single_trailing_underscore_ : used by convention to avoid conflicts with Python keyword, eg

Tkinter.Toplevel(master, class_='ClassName')

Answer 2

The answer of class_ from PEP 8 is awkward, in my opinion, and possibly problematic as commented elsewhere for that answer to this question. The PyCharm IDE seems to prefer cls for class methods, which annoys me for its coder-happy abbreviation, while the arguably more or less readable and understandable klass is still a misspelling. So I'd like to throw out an alternative for these situations, including class wrappers and the like:

I use Class , which is not reserved due to the casing.

I know a lot of people are going to say that variables names should be lowercase, but the lines between object and type, class and function, variable and pre-defined are all blurred in Python. For instance, if I were to write:

NoneType = type(None)

would you argue that it should be renamed NONE_TYPE because it's global? NoneType is a class, though it is not defined using the class keyword. Likewise Class is a class, although it's also a variable. By capitalizing it, I'm just emphasizing one aspect over another. And I do this for all variables representing types.

Answer 3

There isn't really a convention. I've seen - and probably used - klass , _class , and cls .