关于Python中的向量相加和numpy中的向量相加效率对比

            
# -*-coding:utf-8-*-
#向量相加
def pythonsum(n):
 a = range(n)
 b = range(n)
 c = []
 for i in range(len(a)):
  a[i] = i**2
  b[i] = i**3
  c.append(a[i]+b[i])
 return a,b,c

print pythonsum(4),type(pythonsum(4))
for arg in pythonsum(4):
 print arg

          

            
([0, 1, 4, 9], [0, 1, 8, 27], [0, 2, 12, 36]) 
            
              
[0, 1, 4, 9]
[0, 1, 8, 27]
[0, 2, 12, 36]
            
          

            
def numpysum(n):
 a = np.arange(n) ** 2
 b = np.arange(n) ** 3
 c = a + b
 return a,b,c
          

            
(array([0, 1, 4, 9]), array([ 0, 1, 8, 27]), array([ 0, 2, 12, 36])) 
            
              
[0 1 4 9]
[ 0 1 8 27]
[ 0 2 12 36]
            
          

            
size = 1000
start = datetime.now()
c = pythonsum(size)
delta = datetime.now() - start
# print 'The last 2 elements of the sum',c[-2:]
print 'pythonSum elapsed time in microseconds',delta.microseconds

size = 1000
start1 = datetime.now()
c1 = numpysum(size)
delta1 = datetime.now() - start1
# print 'The last 2 elements of the sum',c1[-2:]
print 'numpySum elapsed time in microseconds',delta1.microseconds

          

            
pythonSum elapsed time in microseconds 1000
numpySum elapsed time in microseconds 0