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# A simple vector class
def vec(*v):
return apply(Vec, v)
class Vec:
def __init__(self, *v):
self.v = []
for x in v:
self.v.append(x)
def fromlist(self, v):
self.v = []
if type(v) <> type([]):
raise TypeError
self.v = v[:]
return self
def __repr__(self):
return 'vec(' + `self.v`[1:-1] + ')'
def __len__(self):
return len(self.v)
def __getitem__(self, i):
return self.v[i]
def __add__(a, b):
# Element-wise addition
v = []
for i in range(len(a)):
v.append(a[i] + b[i])
return Vec().fromlist(v)
def __sub__(a, b):
# Element-wise subtraction
v = []
for i in range(len(a)):
v.append(a[i] - b[i])
return Vec().fromlist(v)
def __mul__(self, scalar):
# Multiply by scalar
v = []
for i in range(len(self.v)):
v.append(self.v[i]*scalar)
return Vec().fromlist(v)
def test():
a = vec(1, 2, 3)
b = vec(3, 2, 1)
print a
print b
print a+b
print a*3.0
test()
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