class method vs static method

[Marc 'BlackJack' Rintsch]

In <1164098781.577358.90850 at j44g2000cwa.googlegroups.com>, Chris Brat
wrote:

> I've done some reading up but I cant get my head around how/why class
> methods can be used as apposed to static methods.
> 
> Can anyone give an example of where they have used class methods?

----
class Spam(object):
    def __init__(self, data):
        self.data = data
    
    @classmethod
    def load(cls, filename):
        # Open file and load data.
        data = 'eric'
        return cls(data)

class Ham(Spam):
    pass

ham = Ham.load('test.dat')
print type(ham)
----

Here the type of `ham` is ``<class '__main__.Ham'>`` because a class
method will receive the class on which the method is called as first
argument. In a static method you don't know if it is called on the class
where the method is defined or on a subclass.

Ciao,
	Marc 'BlackJack' Rintsch