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):

    if not s: # a base case ...

       return ""

    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]