import time

#循环生成器

def traversal_list(alist, i):

    while True:

        length = len(alist)

        i = i%(length)

        yield alist[i]

        i += 1

def traversal_list2(alist):

    i = 0

    f = traversal_list(alist, i)

    while True:

        a = next(f)

        print(a)

        time.sleep(1)

        i += 1

if __name__ == '__main__':

    alist = [1, 2, 3, 4, 5]

    traversal_list2(alist)