source: downloads/ogre/Tools/Wings3DExporter/vector.py @ 48

import math

class Vector:

        rep = None

        def __init__(self, x, y=None, z=None, w=None):
                if y == None: 
                        self.rep = tuple(x)
                elif z == None:
                        self.rep = (x, y)
                elif w == None:
                        self.rep = (x, y, z)
                else:
                        self.rep = (x, y, z, w)

        # math functions

        def __add__(self, other):
                return Vector(map(lambda a, b: a + b, self.rep, other.rep))

        def __sub__(self, other):
                return Vector(map(lambda a, b: a - b, self.rep, other.rep))

        def __mul__(self, value):
                return Vector(map(lambda x: x * value, self.rep))

        def __div__(self, value):
                return Vector(map(lambda x: x / value, self.rep))

        def __abs__(self):
                "absolute gives the length"
                return math.sqrt(self % self)

        def __neg__(self):
                return Vector(map(lambda x: -x, self.rep))
                                
        def __mod__(self, other):
                "dot product"
                return self.dot(other)

        def __xor__(self, other):
                "3d cross product"
                return self.cross(other)

        # coord access functions

        def __len__(self):
                return len(self.rep)

        def __getitem__(self, index):
                return self.rep[index]

        def __getattr__(self, name):
                name_indices = {'x':0, 'y':1, 'z':2, 'w': 3, 'u': 0, 'v': 1}
                if not name_indices.has_key(name): raise AttributeError(name)
                return self.rep[name_indices[name]]

        # other useful basic functions

        def __eq__(self, other):
                return 0 not in map(lambda a, b: a == b, self.rep, other.rep)

        def __ne__(self, other):
                return 0 in map(lambda a, b: a == b, self.rep, other.rep)

        def __nonzero__(self):
                return max(map(lambda x: abs(x), self.rep)) > 0

        # string conversion functions

        def __str__(self):
                s = ",".join(map(lambda x: "%.3f" % x, self.rep))
                return '(' + s + ')'

        def __repr__(self):
                s = ",".join(map(lambda x: "%.3f" % x, self.rep))
                return 'Vector(' + s + ')'

        # other functions

        def dot(self, other):
                temp = map(lambda x, y: x * y, self.rep, other.rep)
                return reduce(lambda a, b: a + b, temp)

        def cross(self, other):
                a1, a2, a3 = self
                b1, b2, b3 = other
                return Vector(a2*b3 - a3*b2, a3*b1 - a1*b3, a1*b2 - a2*b1)

        def normalize(self):
                len = abs(self)
                if len < 1e-5: raise ValueError('zero vector')
                self.rep = tuple(map(lambda x: x / len, self.rep))

        def unit(self):
                len = abs(self)
                if len < 1e-5: raise ValueError('zero vector')
                return self / len

# test
if __name__ == "__main__":
        a = Vector(0,3,4)
        b = Vector(1,2,5)

        print a, b
        print a + b
        print abs(a)
        print a + Vector(1,0,0)
        print a ^ b
        x, y, z = a
        print x, y, z