How to implement a constructor for an abstract base class?

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I am trying to write a base abstract class that has some properties that will be initialized using a constructor. So far I have this:

from abc import ABC, abstractmethod

class A(ABC):
    def __init__(self, n, *params):
        self.n = n
        self.initialize_params(*params) #I want to do this in all subsclasses of A
    def initialize_params(self, *params)
       pass
    @abstractmethod
    def do(self):
        pass

class B(A):
    def __init__(self, m, n, *super_params):
        self.m = m
        super(A, self).__init__(n, *super_params)
    def do(self):
        print("this is B")

But this will throw TypeError because of instantiation of A in __init__ of B. What is the correct way of doing this?

abc abstract-class python-3.x inheritance python
1 Answers

You seem to have a couple of mistakes:

from abc import ABC, abstractmethod

class A(ABC):
    def __init__(self, n, *params):
        self.n = n
        self.initialize_params(*params) #I want to do this in all subsclasses of A
    def initialize_params(self, *params):
        pass
    @abstractmethod
    def do(self):
        pass

class B(A):
    def __init__(self, m, n, *super_params):
        self.m = m
        super().__init__(n, *super_params)  # correct way to use super() to call init
    def do(self):
        print("this is B")


b = B(1,2)
b.do()

Note that you missed self. infront of initialize_params() and you didn't seem to be using super() correctly.

quamrana_48340
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