Python second level inheritance

Question

I'm kinda new to python, but I've got a question about second level inheritance.

I have this situation:

class A:
  def Something(self):
     #Do Stuff

class B(A):
  def SomethingElse(self):
     #Do other stuff

class C(B):
  def Something(self):
     #Do additional stuff

Note that class C inherits from B which inherits from A, but that class B DOES NOT implement method Something().

If I call super(C, self).Something() for an instance of class C, what will happen? Will it call the method from class A?

Additionally, if class B does implement Something(), but I want to call class A's Something() directly from class C (ie bypass class B's implementation), how do I do it?

Finally, can someone explain to me why people user super() rather than just calling the parent class's methods directly? Thanks.

Daniel Roseman · Accepted Answer · 2013-06-24 13:03:34Z

11

In the first case, where B does not implement Something, calling super will fall up to the place where it is defined, ie A.

In the second case, you can bypass B by calling A.Something(self).

The main reason for using super is for those cases where you have multiple inheritance: Python will always call the next definition in the MRO (method resolution order).

See Raymond Hettinger's excellent article Super considered super!.

answered Jun 24, 2013 at 13:03

Daniel Roseman

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viraptor · Accepted Answer · 2013-06-24 13:01:55Z

5

Yes, it will call Something() from the A class.
You can always call A.Something(self) from C.

Explanation for super() and other calling conventions would take a while. Have a look at the original article about MRO and Python's Super is nifty, but you can't use it.

answered Jun 24, 2013 at 13:01

viraptor

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