生成式和生成器

L = []
 for x in range(1, 11):
    L.append(x * x)
print (L)

[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

>>> [x * x for x in range(1, 11)]
[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]

a = [x*x for x in xrange(10) if x*x%2 == 0]    ##if判断x*x是偶数，就保留
print(type(a))
print(a)

<type ‘list‘>
[0, 4, 16, 36, 64]

a = (x*x for x in xrange(10) if x*x%2 == 0)
print(type(a))
print(a.next())
print(a.next())
print(‘aaaaaaa‘)
for i in a:
print(i)

<type ‘generator‘>
0
4
aaaaaaa
16
36
64

def fib(n):
    sum = 0
    i = 0
    while(i<n):
        sum = sum +i
        i+=1
        yield sum
for x in fib(10):
print(x)
print(type(fib(10)))

0
1
3
6
10
15
21
28
36
45
<type ‘generator‘>