python_yield

def xranges():
    print("111")
    yield 1
    print("222")
    yield 2
    print("333")
    yield 3

x = xranges()
#打印输出
r = x.__next__()
#返回yield的返回值
print(r)
r = x.__next__()
print(r)

仿写range

def xrangs(n):
    i = 0
    while True:
        if i>n:
            return
        yield i
        i +=1