python 中实现字符串反转的几种方法

>>> str1 = "abcdef"           ## 测试字符串
>>> str1[::-1]
'fedcba'

>>> str1 = "abcdef"             ## 测试字符串
>>> rev = ""
>>> for i in str1:              ## 循环结构实现反转
...     rev = i + rev
...
>>> print(rev)
fedcba

>>> str1 = "abcdef"               ## 测试字符串
>>> rev = reversed(str1)          ## 实现逆转
>>> print("".join(rev))
fedcba