Python - do I need to learn about old style classes?

Question

I am currently learning Python 2.6.5 and I found out about old style classes and new style classes.

I understand that these classes are still existing only for backward compatibility and that they are removed in Python 3.

So the question is this: as a newcomer to the language, do I need to learn about the classic classes?

P.S. I am learning Python 2 because Python 3 is still not fully supported in frameworks and I want to learn some frameworks too. The plan will be to move to Python 3 when frameworks catch up, but until then, do I need to worry about the old style classes?

Answer 1

No. Don't bother. Simply inherit all your classes from object (or from classes that inherit from object) and you will be good to go. Then when you transition to Python 3 you can forget that bit of syntax.

There's no advantage to using or even learning about old-style classes at this point.

So just make sure all of your class declarations look like this:

class foo(object):
    ...

(or inherit from something other than object which does inherit from object), and then pretend this is the way that it has always been!

Answer 2

Although I agree with Daniel DiPaolo that you should never need to use old-style classes in your code, there will be times when you will need to understand them a little bit.

For example, with old-style classes you can't use super to call a parent method - and this can bite you when you try and subclass, for example, the urllib2.Request class. If you do this without realising you'll get the cryptic error super() argument 1 must be type, not classobj, which can take ages to debug.

(As you can probably tell, I've been there...)