11.初探python之生成器

#列表生成式
a = [x for x in range(10)]
print(a)

def f(n):
    return n**3
b = [f(x) for x in range(10)]
print(b)
#生成器
#创建方法1
s = (x*2 for x in range(10))
#print(next(s))#一次只能调用一个，按顺序调用 next(s)==s.__next__()
for i in s:
    print(i)
#创建方法2 yield
def gen():
    print('ok1')
    yield 1   #返回1
    print('ok2')
    yield 2
g=gen()
next(g)
next(g)
#斐波那契数列
def fib(max):
    n,before,after = 0,0,1
    while n < max:
        yield before
        before,after = after,before+after
        n = n+1
a = fib(10)
for i in a:
    print(i)
#send
def bar():
    count = yield 1
    print(count)
b = bar()
b.send(None) #b.send(None)==next(b),send方法第一次需要传入None，后面的传入值会传給yield前面的变量
b.send('aaa')