CODEWITHSUNDEEP
pythonoopfunctionmetaclass
weeb
weeb

Reputation: 1991

Python override a function/method without retyping function arguments

For example I have

class A:
    def f(self, x, y, z):
        # do something with x, y, z

Is it possible to override f without retyping "self, x, y, z". Basically I have a class with function with 10 arguments, and intend on having many classes extending it, so I would prefer not to type the arguments every time. Please do not just tell me to pass a list/dictionary of all the arguments.

Upvotes: 2

Views: 3331

Answers (2)

BoppreH
BoppreH

Reputation: 10193

class A:
    def facade_f(self, x, y, z):
        self._real_f({'x': x, 'y': y, 'z': z})

    def _real_f(self, params):
        # do something with params['x'], params['y'], params['z']

class B(A):
    def _real_f(self, params):
        # do something with params['x'], params['y'], params['z']

It's not a true overriding, but you expose a nice interface with all named parameters, can check their types and values in the facade_f method, and still type very little when extending it.

Working example:

class A:
    def facade_f(self, x, y, z):
        self._real_f({'x': x, 'y': y, 'z': z})

class B(A):
    def _real_f(self, params):
        print params['x'], params['y'], params['z']

B().facade_f(1, 2, 3)

Upvotes: 2

BrenBarn
BrenBarn

Reputation: 251618

No. If you want the overridden function to have the same arguments, you need to type the same arguments. You could override it to have different arguments, so there's no way to magically know that you want it to have the same arguments.

The only way to avoid this is to use *args and/or **kwargs, but you seem to be saying you don't want to do that. (Also, this is not quite the same as actually defining the function with the right arguments, in terms of where/when errors are raised if you call with the wrong arguments.)

Upvotes: 4

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