Types and classes in Python

Question

I\'m a bit confused about types and classes in Python. For e.g. the following REPL conversation confuses me:

>>> class A: pass
... 
>>> a = A()         


        

Answer 1

You're encountering the different behavior for new style classes versus classic classes. For further reading read this: Python Data Model. Specifically read the section on classes and the difference between new style and classic classes.

Try typing the following into your REPL:

class A: pass
class B(object): pass

and you'll see that you get different results. Here you're dealing with the difference between new style and old style classes. Using Python 2.6.1 here's what I get:

> type(A)

> type(B)

which tells you that lists are new style classes and not old style classes. We can further play around with things using list as well:

> type(list)

same as our class B(object): pass result. And also

> c = []
> type(c)

which is telling you about the instance of the object and not it's definition.