User Defined __mul__ Method Is Not Commutative

I wrote a class to represent vectors in Python (as an exercise) and I'm having problems with extending the built-in operators. I defined a __mul__ method for the vector class. The

Solution 1:

If you want commutativity for different types you need to implement __rmul__(). If implemented, it is called, like all __r*__() special methods, if the operation would otherwise raise a TypeError. Beware that the arguments are swapped:

classFoo(object):
    def__mul_(self, other):
        ''' multiply self with other, e.g. Foo() * 7 '''def__rmul__(self, other):
        ''' multiply other with self, e.g. 7 * Foo() '''

Solution 2:

I believe you are looking for __rmul__