yield的使用例子——斐波那契数列

def fib():
    a, b = 0, 1
    while True:
        yield b
        a,b=b,a+b
a=fib()
print(next(a))
print(next(a))
print(next(a))
print(next(a))
print(next(a))

也可以限制个数

def fib(total):
    n,a, b =0, 0, 1
    while n