python加密程序中int（）的问题

Question

我需要确保cypher的输入移位是整数。我如何确保它是这样的，到目前为止，当我在任何输入中使用int（）变量时，即使我输入一个整数，它也会产生错误。

这是代码，用2.7.6编写和编译

 import re

def caesar(plain_text, shift):
    cipherText = ''
    for ch in plain_text:
      stayInAlphabet = ord(ch) + shift
      if ch.islower():
        if stayInAlphabet > ord('z'):
          stayInAlphabet -=26
        elif stayInAlphabet < ord('a'):
          stayInAlphabet += 26
      elif ch.isupper():
        if stayInAlphabet > ord('Z'):
          stayInAlphabet -= 26
        elif stayInAlphabet < ord('A'):
          stayInAlphabet += 26
      finalLetter = chr(stayInAlphabet)
      cipherText += finalLetter
    print(cipherText)
    return cipherText

selection = input ("encrypt/decrypt ")
if selection == 'encrypt':
  plainText = input("What is your plaintext? ")
  shift = (int(input("What is your shift? ")))%26
  caesar(plainText, shift)

else:
  plainText = input("What is your plaintext? ")
  shift = ((int(input("What is your shift? ")))%26)*-1
  caesar(plainText, shift)

Answer 1

对于python 2.7，您希望使用raw_input而不是input。有关详细信息，请参阅this post。