Python new-style classes and the super() function

12 July 2008   5 comments   Python

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I've never really understood the impact of new-style Python classes and what it means to your syntax until now. With new-style classes you can use the super() builtin, otherwise you can't. This works for new-style classes:

class Farm(object):
   def __init__(self): pass

class Barn(Farm):
   def __init__(self):
       super(Barn, self).__init__()

If you want to do the same for old-style classes you simply can't use super() so you'll have to do this:

class Farm:
   def __init__(self): pass

class Barn(Farm):
   def __init__(self):

Strange that I've never realised this before. The reason I did now was that I had to back-port some code into Zope 2.7 which doesn't support setting security on new-style classes.

Now I need to do some reading on new-style classes because clearly I haven't understood it all.


Super is not a function, it's a type (surprise)
Paul Hildebrandt
Property is one of my favorite things about new style classes. They can make something akward seem more pythonic.
Peter Bengtsson
I like the syntax and the look of them but rarely use it. I find it a little bit a solution to a problem that isn't really a problem. In the real world you either just leave the attributes as they are and/or you write full-blown attribute getters/setters that mix in business logic or other legacy fixing logic.
You *can* use super, but you shouldn't.
Talat Parwez
In older version of python; for super keyword we use to give as:
    super(current_class_name, self).method_name()

But for newer version of python or say new style classes we can simply give:

What it'll do is to pass the control to the parent class instead of performing execution for current class.

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