Difference in Python class declaration

Question

In python class declaration I can declare a class by few ways. What is a difference between following samples?

class MyClass:
 def __init__(self)
     pass


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

An important question, but one that could have obviously been answered 'self-serve' by reading the docs.. — wim, Jan 03 '12 at 11:09

Russell Dias · Answer 1 · 2012-01-03T12:43:02.850

7

The second declaration creates a new-style class. A new-style class is derived from a built-in type, in this case an object. This was introduced in python 2.2 in an effort to unify classes and types. For backward compatibility old-style classes are still the default

Additional read: http://docs.python.org/release/2.2.3/whatsnew/sect-rellinks.html

edited Jan 03 '12 at 12:43

answered Jan 03 '12 at 11:02

Russell Dias

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FTR, in Python 3 there is no difference between these 2 syntaxes. – Michael Merickel Jan 03 '12 at 11:05

score 2 · Accepted Answer · answered Jan 03 '12 at 11:14

The second way creates a "new-style" class. Documentation is admittedly a bit lacking, as mentioned in a couple places on the python website Python Guide 3.3, and here. There's also an essay describing their design by Python's creator (Guido van Rossum), but it's not strictly documentation.

Difference in Python class declaration

2 Answers2