凯撒密码只返回第一封翻译的信？

Question

为什么加密函数只返回第一个翻译的字母？（我去掉了解密和暴力功能）。这个问题可能是一个小问题，但我是新来的，我已经盯着它太久了，任何东西弹出我的脑海。你知道吗

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encrypt函数应该等到循环结束后返回： 另外请注意，如果字符不是大写或小写，则应附加字符，否则只会返回错误的第一个字母。
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

Answer 2

将return语句放入循环中。这意味着在第一次迭代之后，您将退出函数，结果只有一个字符。你知道吗

您的代码应该如下所示：

cryptotext = ""
for character in message:
    # ...
    # do the encryption, without returning
    # ...
return cryptotext # after the loop has finished