Python inheritance – how to call grandparent method?

Question

Consider the following piece of code:

class A:
  def foo(self):
    return "A"

class B(A):
  def foo(self):
    return "B"

class C(B):
  def foo(self):
    tmp = ... # call A's foo and store the result to tmp
    return "C"+tmp

What shall be written instead of ... so that the grandparent method foo in class A is called? I tried super().foo(), but it just calls parent method foo in class B.

I am using Python 3.

Asked By: karlosss

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Source

Answer 1

You can explicity call the method from the grandparent class:

class C(B):
    def foo(self):
       tmp = A.foo()
       return "C" + tmp

Answered By: Robert Valencia

Answer 2

You can simply be explicit about the class. super() allows you to be implicit about the parent, automatically resolving Method Resolution Order, but there’s nothing else that’s special about it.

class C(B):
    def foo(self):
       tmp = A.foo(self)
       return "C"+tmp

Answered By: Julien

Answer 3

Calling a parent's parent's method, which has been overridden by the parent
There is an explanation in this discuss already on how to go back in the tree.

Answered By: Zed Evans

Answer 4

There are two ways to go around this:

Either you can use A.foo(self) method explicitly as the others have suggested – use this when you want to call the method of the A class with disregard as to whether A is B‘s parent class or not:

class C(B):
  def foo(self):
    tmp = A.foo(self) # call A's foo and store the result to tmp
    return "C"+tmp

Or, if you want to use the .foo() method of B‘s parent class regardless of whether the parent class is A or not, then use:

class C(B):
  def foo(self):
    tmp = super(B, self).foo() # call B's father's foo and store the result to tmp
    return "C"+tmp

Answered By: Alexander Rossa

Python inheritance – how to call grandparent method?

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