A class method which behaves differently when called as an instance method?

Question

I\'m wondering if it\'s possible to make a method which behaves differently when called as a class method than when called as an instance method.

For example, as a skill

Answer 1

[edited: use attribute to be a more direct answer; see the helpful comment by John Fouhy]

You can use a descriptor to do what you want:

class cls_or_inst_method(object):
    def __init__(self, class_method, instance_method):
        self.class_method = class_method
        self.instance_method = instance_method

    def __get__(self, obj, objtype):
        if obj is None:
            return self.class_method
        else:
            return lambda: self.instance_method(obj)

def my_class_method(baz):
    return baz + 1

def my_instance_method(self):
    return self.baz * 2

class Foo(object):
    baz = 10
    bar = cls_or_inst_method(my_class_method, my_instance_method)

Using the above:

>>> print Foo.bar(5)
6
>>> my_foo = Foo()
>>> print my_foo.bar()
20