Call Python non-member function referenced by class variable

Question

In my class I'd like to call a non-member function whose reference is stored in a member variable. My issue is that it tries to pass self to the function as the first argument. How can I avoid this?

class MyClass:
    my_useful_static_function = crcmod.mkCrcFun(0x11021, True)

    def __init__(self):
        # this gets called with the first argument as self :(
        result = self.my_useful_static_function()

score 3 · Accepted Answer · answered May 02 '19 at 12:15

3

Use staticmethod:

class MyClass:
    my_useful_static_function = staticmethod(crcmod.mkCrcFun(0x11021, True))

    def __init__(self):
        result = self.my_useful_static_function()

answered May 02 '19 at 12:15

Aran-Fey

39,665
11
104
149

Tested, works :) – Rick May 02 '19 at 12:17

score 0 · Answer 2 · answered May 02 '19 at 12:15

0

You need to use staticmethod like so:

class Foo: 
    @staticmethod 
    def my_method(): 
        print("This is a static method") 

    def my_other_method(self): 
        print("This is not static")

# This works
Foo.my_method()

# This won't work
Foo.my_other_method()

# This works though
foo_instance = Foo()
foo_instance.my_other_method()

answered May 02 '19 at 12:15

Silvano Cerza

954
5
16

1

In this instance I'm not creating the def, so I don't think `@staticmethod` works, but the function format does. – Rick May 02 '19 at 12:16
Right, I missed that part. – Silvano Cerza May 02 '19 at 12:18
1

@Rick: `@staticmethod` is just syntactic sugar for `decoratedname = staticmethod(decoratedname)`. – Martijn Pieters May 02 '19 at 12:19

Call Python non-member function referenced by class variable

2 Answers2