What can I do with a Python class method that I can't do with a Python static method?

Classmethods take the class on which the method was called as their first argument; this enables some cool polymorphism with classes. Here's one use-case I'm using in production now. I'm using SQLAlchemy and have a base class for my model classes that defines a find() wrapper around sqlalchemy's query(), like this: class BaseModel(object): @classmethod def find(cls, **kw): return session.query(cls).filter_by(**kw).one() class User(BaseModel): pass Since the first argument to the classmethod is the class the method is being called one, I can call User.find() and it's as if I had written the following: class User(BaseModel): @staticmethod def find(**kw): return session.query(User).filter_by(**kw).one() except that I don't have to duplicate the definition of find() for every one of my model classes.

In a static method, you have to refer to the current class by name. class A(object): @staticmethod def foo(): print 'foo' A.bar() @staticmethod def bar(): print 'bar' class B(A): @staticmethod def bar(): print 'new bar' Now when you call `B.foo()`, the `B.bar` won't override `A.bar` like when we use classmethod.

classmethod is an attribute of the class, just like a normal method is an attribute for some instance of class. Its first argument is cls, which like self in normal methods is implicit. Static methods are neither attached to classes or their instances Both static method and class method are put into the 'class type' object at the same time (ie when the code of class is executed), so I think there is no difference in their performances (ie in speed). They both are coexisting just because they can be used for different types of jobs. A classmethod is a cool way to do things with intantiation (the cls argument of it is callable as cls() thus running the __init__ method of class,so overriding in subclasses is possible) while staticmethod is good for dependency injection(using function of some other module in our class thorugh its instances). E.g., >>> class myList(list): def getListFromKeys(cls,dicti): return cls(dicti) getListFromKeys=classmethod(getListFromKeys) >>> a=myList() >>> b=a.getListFromKeys({'a':'apple'}) >>> b ['a'] >>> Static Method is to use some method declred in some other module into our class and use it by the instances of our class. There is no other way to call a method of class with the first argument not being cls or self

See, e.g., http://rapd.wordpress.com/2008/07/02/python-staticmethod-vs-classmethod/ http://go2.wordpress.com/?id=725X1342&site=rapd.wordpress.com&url=http%3A%2F%2Fmail.python.org%2Fpipermail%2Fpython-list%2F2007-July%2F450345.html