我需要从一个字符串中获取第一个字母，并使其成为python中其他字符串中另一个字母的索引

Question

我是编程新手，所以我从一门关于 python 的课程开始，在这门课程中我发现了这个我不知道该怎么做的练习，所以如果有人可以帮助我

>def cipher(map_from, map_to, code):
   """ map_from, map_to: strings where each contain 
                          N unique lowercase letters. 
      code: string (assume it only contains letters also in map_from)
        Returns a tuple of (key_code, decoded).
        key_code is a dictionary with N keys mapping str to str where 
        each key is a letter in map_from at index i and the corresponding 
        value is the letter in map_to at index i. 
        decoded is a string that contains the decoded version 
        of code using the key_code mapping. """

例如，

cipher("abcd", "dcba", "dab") 返回（字典中的条目顺序可能不一样）({'a':'d', 'b': 'c', 'd': 'a', 'c': 'b'}, 'adc')

Answer 1

字符的索引从 0 开始。这应该提供一个提示：

>>> 'abcdefgh'.find('e')
4
>>> 'abcdefgh'[4]
'e'