python join()颠倒链接字符串

#!/usr/bin/python
# -*- coding: UTF-8 -*-

str_1 = input("输入一个字符串：")
len1 = len(str_1) - 1
str_list = []
while(len1 >= 0):
    str_list.append(str_1[len1])
    len1 = len1 - 1
    print(''.join(str_list))

输入一个字符串：我们的太阳放光忙

忙

忙光

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忙光放阳太

忙光放阳太的

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忙光放阳太的们我