python - 凯撒密码只返回第一个翻译的字母？

Question

为什么我的加密函数只返回第一个翻译后的字母？ (我已经删除了解密和蛮力功能)。这个问题可能是一个小问题，但我对此并不陌生，而且我已经盯着它看了太久，以至于我脑子里什么都想不起来。

import string

def encrypt(message,key):
    cryptotext=""
    for character in message:
        if character in string.uppercase:
            old_ascii=ord(character)
            new_ascii=(old_ascii+key-65)%26+65
            new_char=chr(new_ascii)
            cryptotext+=new_char
            return cryptotext

        elif character in string.lowercase:
            old_ascii=ord(character)
            new_ascii=(old_ascii+key-97)%26+97
            new_char=chr(new_ascii)
            cryptotext += new_char
            return cryptotext

        else:
            return character

Answer 1

return 语句从当前循环中断，这意味着加密函数应该等到循环结束后返回:另请注意，如果字符不是大写或小写，则应附加该字符，否则它只会返回第一个错误的字母。
所以 encrypt(message,key) 应该是这样的:

def encrypt(message,key):
    cryptotext=""
    for character in message:
        if character in string.uppercase:
            old_ascii=ord(character)
            new_ascii=(old_ascii+key-65)%26+65
            new_char=chr(new_ascii)
            cryptotext+=new_char


        elif character in string.lowercase:
            old_ascii=ord(character)
            new_ascii=(old_ascii+key-97)%26+97
            new_char=chr(new_ascii)
            cryptotext += new_char


        else:
            #Also, append character to cryptotext instead of returning it
            cryptotext+= character
    return cryptotext