inheritance with recursive method override-CodePudding

class A:
    def m(self, v):
        for i in range(v):
          print("A")
          self.m(v-1)

class B(A):
    def m(self, value):
        print("B")
        super(B, self).m(value)

B().m(3)

Output: B A B A B A

Expected output: BAAAA

On class A, the self object is of B and it's calling method m of class B, but I don't want this to happen.

I know I can change the method name, but that is a constraint, I can not change the name of method.

CodePudding user response：

You can temporarily overwrite self.m in your instance of B. This makes it so that you don't need to change the definition of A

class A:
    def m(self, v):
        for i in range(v):
          print("A")
          self.m(v-1)

class B(A):
    def m(self, value):
        print("B")
        mB = self.m
        self.m = super(B, self).m
        self.m(value)
        self.m = mB

B().m(3)

CodePudding user response：

This is certainly a contrived example but you could use a keyword argument that defaults to 0 and a conditional expression that only prints the "B" if the argument is 0, and then increment the argument on subsequent calls.

For example:

class A:
    def m(self, v, count=0):
        for i in range(v):
            print("A")
            self.m(v-1, count=count 1)

class B(A):
    def m(self, value, count=0):
        if count == 0:
            print("B")
        super().m(value, count=count    1)

B().m(3)

output:

B
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A