Abstract classes with varying amounts of parameters

Question

I was wondering if its possible when creating an abstract class with abstract methods if its possible to allow the implementations of those methods in the derived classes to have different amounts of parameters for each function.

I currently have for my abstract class

from abc import ABCMeta, abstractmethod

class View(metaclass=ABCMeta):
    @abstractmethod
    def set(self):
        pass

    @abstractmethod
    def get(self):
        pass

But I want to be able to implement it in one class with set having 1 parameter and get having 2
(set(param1) and get(param1, param2)),
and then in another class also inherit it but have 0 parameters for set and 2 for get
(set() and get(param1, param2)).

Is this possible and if so how would I go about doing it

Asked By: 1seanr

||

Source

Answer 1

No checks are done on how many arguments concrete implementations take. So there is nothing stopping your from doing this already.

Just define those methods to take whatever parameters you need to accept:

class View(metaclass=ABCMeta):
    @abstractmethod
    def set(self):
        pass

    @abstractmethod
    def get(self):
        pass


class ConcreteView1(View):
    def set(self, param1):
        # implemenation

    def get(self, param1, param2):
        # implemenation


class ConcreteView2(View):
    def set(self):
        # implemenation

    def get(self, param1, param2):
        # implemenation

Answered By: Martijn Pieters

Answer 2

python 3.8

from abc import ABC, abstractmethod


class SomeAbstractClass(ABC):
    @abstractmethod
    def get(self, *args, **kwargs):
        """
        Returns smth
        """

    @abstractmethod
    def set(self, key, value):
        """
        Sets smth
        """

class Implementation(SomeAbstractClass):
    def set(self, key, value):
        pass

    def get(self, some_var, another_one):
        pass

Works perfectly, no warnings, no problems

Answered By: n0nSmoker

Abstract classes with varying amounts of parameters

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