反转字符串递归错误python

Question

当我返回 .join 方法来反转字符串时，我调用函数本身来这样做。如何在不使用内置 Python 方法（例如 reversed 方法）的情况下反转此字符串。

def reverse_string_3(string):

    length = len(string)

    spaces = [' ']

    words = []

    index_tracker = 0

    while index_tracker < length:

        if string[index_tracker] not in spaces:

            beginning_of_word = index_tracker

            # we only want to increment when the index tracker is a letter and not spaces

            while index_tracker < length and string[index_tracker] not in spaces:

                index_tracker += 1

            words.append(string[beginning_of_word:index_tracker])

        index_tracker += 1

    return "".join(reverse_string_3(string)) 

Answer 1

def reverse_string(s):&nbsp; &nbsp; if not s: # a base case ...&nbsp; &nbsp; &nbsp; &nbsp;return ""&nbsp; &nbsp; return s[-1] + reverse_string(s[:-1]) # a recursive case尽管这些会产生可怕的示例问题，因为现实世界中的任何人都会使用reverse或s[::-1]