Use of super () in python

Question

When I execute the following:

class animal(object):
      def desc(self):
             print 'animal'
class human():
      def desc(self):
              print 'human'
class satyr(human, animal):
      def desc(self):
              print 'satyr'

grover=satyr()
super(satyr, grover).desc()

I get human! But human did not even inherit the class object, and I think super works only if class object is inherited. (New style class)

Now if I make animal also not inherit class object, I get an error. What is going on here?

possible duplicate - http://stackoverflow.com/questions/3277367/how-does-pythons-super-work-with-multiple-inheritance — Brendan Abel, Jan 20 '16 at 09:22
@Brendan, no it is not. I read that already. That one asks about the left to right approach of python. — Mahathi Vempati, Jan 20 '16 at 09:28
@TomaszJakubRup your edit specifically removed the issue the OP was asking about. Please don't do that. — Daniel Roseman, Jan 20 '16 at 09:31
I do not want human to inherit from object. Please don't edit my code to change that. That is the point of the question. — Mahathi Vempati, Jan 20 '16 at 09:31

score 2 · Accepted Answer · edited May 23 '17 at 12:15

2

It works that way because only one of the classes or inherited classes needs to inherit from object in order for your class to be created by the metaclass that object uses. The metaclass controls this MRO behavior.

Here is one of the better answers on stack overflow explaining metaclasses.

In python 3, this is all moot, since everything is a new-style class. Also, there's really no reason NOT to inherit from object, so unless you're forced to use some old library with classes that don't inherit from object, you might as well have all your classes inherit from it.

edited May 23 '17 at 12:15

Community

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answered Jan 20 '16 at 09:37

Brendan Abel

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Thank you. That helped a lot. – Mahathi Vempati Jan 20 '16 at 09:47

Use of super () in python

1 Answers1