生成器是一种特殊的迭代器，它有yield语句

#coding:utf-8
def fibs(max):
    n,a,b = 0,0,1
    while n < max:
        yield b
        a , b = b ,a + b
        n = n + 1
if __name__=="__main__":
    f = fibs(10)
    for i in f:
        print i

output:

1
1
2
3
5
8
13
21
34
55