Demo/classes/Vec.py

   1 # A simple vector class
   2
   3
   4 def vec(*v):
   5     return Vec(*v)
   6
   7
   8 class Vec:
   9
  10     def __init__(self, *v):
  11         self.v = list(v)
  12
  13     def fromlist(self, v):
  14         if not isinstance(v, list):
  15             raise TypeError
  16         self.v = v[:]
  17         return self
  18
  19     def __repr__(self):
  20         return 'vec(' + repr(self.v)[1:-1] + ')'
  21
  22     def __len__(self):
  23         return len(self.v)
  24
  25     def __getitem__(self, i):
  26         return self.v[i]
  27
  28     def __add__(self, other):
  29         # Element-wise addition
  30         v = map(lambda x, y: x+y, self, other)
  31         return Vec().fromlist(v)
  32
  33     def __sub__(self, other):
  34         # Element-wise subtraction
  35         v = map(lambda x, y: x-y, self, other)
  36         return Vec().fromlist(v)
  37
  38     def __mul__(self, scalar):
  39         # Multiply by scalar
  40         v = map(lambda x: x*scalar, self.v)
  41         return Vec().fromlist(v)
  42
  43
  44
  45 def test():
  46     a = vec(1, 2, 3)
  47     b = vec(3, 2, 1)
  48     print a
  49     print b
  50     print a+b
  51     print a-b
  52     print a*3.0
  53
  54 test()