Python - Is it okay to pass self to an external function

python self
elssar picture elssar · Apr 18, 2013 · Viewed 36.3k times · Source

I have a class, A, which is inherited by a bunch of other classes. Some of these have a few functions which are similar and it would be nice to have those functions defined somewhere else and called by the classes that need them. But those functions call functions defined in the super class.

class A():
    def imp_func(*args):
        # called by the child class functions

Class B(A):
    def common_func(self):
        # some stuff
        self.imp_func(*args)

So I have created my helper functions which take the self object as an argument and I can call the imp_func from inside the helper functions.

def helper_func(obj, some_args):
    # some common stuff
    obj.imp_func(*args)

class B(A):
    def common_func(self):
        # unique stuff
        helper_func(self, some_args)

This solves the problem.

But should I be doing this? Is this Pythonic?

Answer

user4815162342 picture user4815162342 · Apr 18, 2013

There is no problem with that whatsoever - self is an object like any other and may be used in any context where object of its type/behavior would be welcome.

In Python, as exemplified by the standard library, instances of self get passed to functions (and also to methods, and even operators) all the time.

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