如何解码编码的句子？

Question

我不太清楚为什么StackOverflow不允许我在下面发布我的代码，所以我附加了一些链接来显示我所做的尝试。在输入完我的句子后，它会将任意数量的字符从1到25进行移动，效果很好。但是，我需要添加一个函数来反转编码，并将原来的句子打印出来。我不太清楚为什么Python会像在第二个链接中那样吐出解码后的句子。它应该有原来的句子。谢谢你的帮助！你知道吗

def encode( ch, shift):
    lower = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWZ'
    if ch not in lower:
        return ch
    newch = chr( ord(ch) + shift )
    if newch not in lower:
        newshift = ( ord(newch) - ord('z') - 1)
        nwech = chr ( ord('a') + newshift )
    return newch

def decoded(ch, shift):
    lower = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWZ'
    if ch not in lower:
        return ch
    newch = chr( ord(ch) + shift )
    if newch not in lower:
        newshift = ( ord(newch) - ord('z') - 1)
        newch = chr ( ord('a') + newshift)
    return newch

def main():
    shift = int(input("Enter a number between 1 and 25:"))
    sentence = input("Please enter a sentence:")
    code = ''
    decode = ''
    for char in sentence:
        code = code + encode (char, shift)
    for char in code:
        decode = decode + encode (char, shift)
    print("Uncoded sentence: " + sentence)
    print("Encoded sentence: " + code)
    print("Decoded sentence: " + decode)

main()

Enter a number between 1 and 25:3
Please enter a sentence:i need help
Uncoded sentence: i need help
Encoded sentence: l qhhg khos
Decoded sentence: o tkkj nkrv

Answer 1

你不能调用decode方法。你调用encode方法两次。。。你知道吗

Answer 2

您的decoded函数似乎与encode函数相同（在任何情况下都不会调用它）。更接近您需要的是：

newch = chr( ord(ch) - shift )

在decoded函数中，您应该在此处调用它来代替encode：

for char in code:
    decode = decode + decoded(char, shift)

但现在你有另一个问题了。如果您的班次将您从字符的ord范围的末尾发送出去，会发生什么情况？你知道吗