Does the @staticmethod decorator do anything?

Question

I made these two classes:

class A:
    @staticmethod
    def f(x):
        print("x is", x)

class B:
    def f(x):
        print("x is", x)

And used them like this:

>>> A.f(1)
x is 1
>>> B.f(1)
x is 1

It looks like f became a static method on B even without the decorator. Why would I need the decorator?

Answer 1

It used to matter more back in Python 2, where the instance-ness of instance methods was enforced more strongly:

>>> class B:
...     def f(x):
...         print("x is", x)
...
>>> B.f(1)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: unbound method f() must be called with B instance as first argument (
got int instance instead)

You had to mark static methods with @staticmethod back then.

These days, @staticmethod still makes it clearer that the method is static, which helps with code readability and documentation generation, and it lets you call the method on instances without the system trying to bind self.

Answer 2

Try these two classes, both having a cry method, one as a classmethod and another as a staticmethod with self passed on

class Cat:

    def __init__(self):
        self.sound = "meow"

    def cry(self):
        print(self.sound)

x = Cat()
x.cry()
meow

and with another class

class Dog:
    def __init__(self):
        self.sound = "ruff-ruff"

    @staticmethod
    def cry(self):
        print(self.sound)

x = Dog()
x.cry()
TypeError: cry() missing 1 required positional argument: 'self'

and we can see the @staticmethod decorator basically removed the passed in self