为什么不加入（）将我的列表变成字符串？

Question

嘿，我只是想知道为什么在这段代码中：

def change_letter(line, what_letter_to_replace, what_to_replace_with):
    """
    This function takes 3 parameters: a string, the letter that is going to be  
    replaced,
    and what it is going to be replaced with.
    """
    lst_line = list(line)
    for letter in lst_line:
        if letter == str(what_letter_to_replace):
            lst_line[lst_line.index(letter)] = str(what_to_replace_with)
    x = ''.join(lst_line)
    y= x.split()
    return y

该函数按预期工作，并返回新更新行中的单词列表，而在这段代码中：

def change_letter(line, what_letter_to_replace, what_to_replace_with):
    """
    This function takes 3 parameters: a string, the letter that is going to be 
    replaced,
    and what it is going to be replaced with.
    """
    lst_line = list(line)
    for letter in lst_line:
        if letter == str(what_letter_to_replace):
            lst_line[lst_line.index(letter)] = str(what_to_replace_with)
    ''.join(lst_line)
    lst_line.split()
    return lst_line

该函数有一个运行时AttributeError，表示＆＃39; list＆＃39;对象没有属性＆＃39; split＆＃39;，但是由于前一行代码已经使lst_line已经成为字符串了吗？

Answer 1

''.join(lst_line)不会影响lst_line。它返回 new 字符串。如果您希望将新字符串称为lst_line，则需要将其分配回该变量：

lst_line = ''.join(lst_line)

请注意，这是第一个示例（它只是将其称为x而不是lst_line）。