解码Ceasar密码最终出现逻辑错误

Question

在编码方面，我是一个完整的初学者，当我遇到这个问题时，我正在在密码期进行培训：

一个国家的士兵使用Ceasar Cipher进行消息传递。只有字母更改，并且在这些消息中没有触摸其他所有内容（例如“！”和空间）。每个消息分为4或5个部分，每个部分由一个跑步者携带。第一部分以2个字母开头：第一个字母显示一个随机字母，第二部分是通过换档更改的同一字母（以便士兵知道班次的数量）。现在编写一个用于解码和编码消息的代码我应该知道您将为我提供一个完美的答案！！！

编码函数有效。但是，我为解码编写的以下功能没有。我输入“ ijj tipvme ibw”，“ f lopxo uibu z”，“ pv xpvme ibwf”，“ b qfsgfdu botx”，“ fs gps nf！”！获取我应该知道您将为我提供一个完美的答案！！，但是我收到一些胡说八道的消息，说'Ž〜〜™ - ''，'，' Š££© - ©®'，'“”€ª€™ - «Š'，' !!!

i导入re首先：

import re

这是功能：

def decode(arr):
    arr = str(arr) #turn what we have into str
    array = list(re.split('",', arr)) #get rid of the ' ", ' between every part so that
                                # it will be a single whole messege in the end and also turn it into
                                #a list in which every item is a single part

    decoded_messege = ""

    first_messege = list(array[0]) #turns the first part into a list of letters
    letter_shift = ord(first_messege[1]) - ord(first_messege[0]) #realizes the number of shift

    for messege in array:
        for letter in messege:
            if (ord(letter) > 122 or ord(letter) < 65): #the letter is not an alphabet (a space or !)
                decoded_messege += letter

            else: #the letter is an alphabet
                decoded_messege += chr(ord(letter) - letter_shift) #the ascii code is the current ascii number
                                                                #minus the shift

    decoded_message = decoded_messege[2:] #ignore the first two letters that are
                                        #only for showing shift and don't matter in the message
    return decoded_messege

Answer 1

问题在于您要考虑到前两个字符来计算偏移：“ - ＆gt; ”是0。将其更改为arr = str（arr）[2：]
另外，返回应处于第一个循环的相同级别。

import re


def decode(arr):
    arr = str(arr)[2:] #turn what we have into str
    array = list(re.split('",', arr)) #get rid of the ' ", ' between every part so that
                                    # it will be a single whole messege in the end and also turn it into
                                    #a list in which every item is a single part

    decoded_messege = ""

    first_messege = list(array[0]) #turns the first part into a list of letters
    letter_shift = ord(first_messege[1]) - ord(first_messege[0]) #realizes the number of shift

    for messege in array:
        for letter in messege:
            if letter != '"':
                # print(letter)
                if (ord(letter) > 122 or ord(letter) < 65): #the letter is not an alphabet (a space or !)
                    decoded_messege += letter
                else: #the letter is an alphabet
                    decoded_messege += chr(ord(letter) - letter_shift) #the ascii code is the current ascii number                                                                    #minus the shift
        decoded_message = decoded_messege[2:] #ignore the first two letters that are
                                            #only for showing shift and don't matter in the message
    return decoded_messege

print(decode('""ijJ tipvme ibw", "f lopxo uibu z", "pv xpvme ibwf ", "b qfsgfdu botx", "fs gps nf!!!""'))
# hiI should hav e known that y ou would have  a perfect answ er for me!!!
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