Python refer to class from within class

Question

I've become aware of @staticmethod - next question, are you supposed to use the class name to refer to these methods from within the class?

class C:
    @staticmethod
    def imstatic():
        print("i'm static")

    @staticmethod
    def anotherstatic():
        # Is this the proper python way?
        C.imstatic()

    @staticmethod
    def brokenstatic():
        # This doesn't work..
        self.imstatic()

Did you try this? The answer should be pretty self evident, but yes. — Silas Ray, Nov 22 '13 at 22:34
Well the reason I asked is because Java and PHP which I'm used to both have keywords for this... — quickshiftin, Nov 22 '13 at 22:35
Note that Python's static method is a different beast from Java and PHP static methods. — Martijn Pieters, Nov 22 '13 at 22:36

score 1 · Accepted Answer · answered Nov 22 '13 at 22:34

1

Yes, as you don't have any other reference to the class from within a static method. You could make these class methods instead, using the classmethod decorator:

class C:
    @staticmethod
    def imstatic():
        print("i'm static")

    @classmethod
    def anotherstatic(cls):
        cls.imstatic()

A class method does have a reference to the class.

answered Nov 22 '13 at 22:34

Martijn Pieters

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Thanks, I believe `@classmethod` is what I'm after. I've now found [this thread](http://stackoverflow.com/questions/136097/what-is-the-difference-between-staticmethod-and-classmethod-in-python) and will keep reading. – quickshiftin Nov 22 '13 at 22:49

score 1 · Answer 2 · answered Nov 22 '13 at 22:34

If you need to refer to the class within a static method you should probably be using a classmethod instead:

class C:
    @staticmethod
    def imstatic():
        print("i'm static")

    @classmethod
    def imclass(cls):
        cls.imstatic()

In the same way that instance methods are "magically" given a reference to the instance as the first argument, class methods are given a reference to the class. You can call them either from an instance or from the class directly, for example both of the following are valid and have the same behavior:

C().imclass()
C.imclass()

That being said, if you do still want to use a static method your current approach is correct, just refer to the class by name.

Also, `self` is only used for instance methods. – SethMMorton Nov 22 '13 at 22:38 — SethMMorton, Nov 22 '13 at 22:38

score 1 · Answer 3 · answered Nov 22 '13 at 22:34

If you always want to call the static method of that specific class, yes, you must specify it by name. If you want to support overriding the static methods, what you want is a classmethod instead: it passes the class on which the method is being called as the first parameter, analogous to self on regular instance methods, so you can call the overridden method. In general I'd suggest using classmethods.

Python refer to class from within class

3 Answers3