雖然循環失敗 - 凱撒密碼

Question

我有一個問題，當我要求我的程序退出時，打印就像我問它，但顯示我的選項菜單以及不斷。

所以我得到這樣的：

>>> 
(S)huffle a message. 
(U)nshuffle a message. 
(Q)uit program. 
Choose a option to begin: q 
Goodbye! 
(S)huffle a message. 
(U)nshuffle a message. 
(Q)uit program. 
Choose a option to continue: 

，我想如果我選擇「Q」它來顯示這一點：

>>> 
(S)huffle a message. 
(U)nshuffle a message. 
(Q)uit program. 
Choose a option to begin: q 
Goodbye! 

這裏是我的完整代碼，請解釋一下爲什麼我的菜單是重新打印，我是否讓我的while循環錯誤，或者是在我的代碼中不合適的地方？

def hw8(): 

    print('(S)huffle a message.') 
    print('(U)nshuffle a message.') 
    print('(Q)uit program.') 

    x = input('Choose a option to begin: ') 

    if x == 'Q' or x == 'q': 
     print('Goodbye!') 

    while x != 'q' or 'Q' : 

     if x == 'S' or x == 's': 
      y = input('Enter a message to shuffle: ') 

      q1 = '' 

      for i in y: 
       if ord(i) in range(65,90) or ord(i) in range(97,122): 
        q = chr(ord(i) + 1) 
        q1 = q1 + q 
       elif ord(i) == 90: 
        q = chr(ord(i) + 7) 
        q1 = q1 + q 
       elif ord(i) == 122: 
        q = 'A' 
        q1 = q1 + q 
       else: 
        q = i 
        q1 = q1 + q 
      print(q1) 



     if x == 'U' or x == 'u': 
      f = input('Enter a message to unshuffle: ') 

      t2 = '' 

      for i in f: 
       if ord(i) in range (66,91) or ord(i) in range(98,123): 
        t = chr(ord(i) - 1) 
        t2 = t2 + t 
       elif ord(i) == 65: 
        t = 'z' 
        t2 = t2 + t 
       elif ord(i) == 97: 
        t = 'Z' 
        t2 = t2 + t 
       else: 
        t = i 
        t2 = t2 + t 

      print(t2) 

     print('(S)huffle a message.') 
     print('(U)nshuffle a message.') 
     print('(Q)uit program.') 

     x = input('Choose a option to continue: ') 


hw8() 

我希望程序洗牌的消息，或unshuffling消息後，以及在開始顯示菜單，而不是在用戶已經要求通過選擇「Q」退出程序。

---

編輯的代碼：

def hw8(): 

    print('(S)huffle a message.') 
    print('(U)nshuffle a message.') 
    print('(Q)uit program.') 

    x = input('Choose a option to begin: ') 

    while x != 'q' or x != 'Q' : 

     if x == 'S' or x == 's': 
      y = input('Enter a message to shuffle: ') 

      q1 = '' 

      for i in y: 
       if ord(i) in range(65,90) or ord(i) in range(97,122): 
        q = chr(ord(i) + 1) 
        q1 = q1 + q 
       elif ord(i) == 90: 
        q = chr(ord(i) + 7) 
        q1 = q1 + q 
       elif ord(i) == 122: 
        q = 'A' 
        q1 = q1 + q 
       else: 
        q = i 
        q1 = q1 + q 
      print(q1) 



     if x == 'U' or x == 'u': 
      f = input('Enter a message to unshuffle: ') 

      t2 = '' 

      for i in f: 
       if ord(i) in range (66,91) or ord(i) in range(98,123): 
        t = chr(ord(i) - 1) 
        t2 = t2 + t 
       elif ord(i) == 65: 
        t = 'z' 
        t2 = t2 + t 
       elif ord(i) == 97: 
        t = 'Z' 
        t2 = t2 + t 
       else: 
        t = i 
        t2 = t2 + t 

      print(t2) 

     print('(S)huffle a message.') 
     print('(U)nshuffle a message.') 
     print('(Q)uit program.') 

     x = input('Choose a option to continue: ') 

     if x == 'Q' or x == 'q': 
      print('Goodbye!') 


hw8() 

新輸出：

>>> ================================ RESTART ================================ 
>>> 

(S)huffle a message. 
(U)nshuffle a message. 
(Q)uit program. 
Choose a option to begin: s 
Enter a message to shuffle: hello 
ifmmp 
(S)huffle a message. 
(U)nshuffle a message. 
(Q)uit program. 
Choose a option to continue: q 
Goodbye! 
(S)huffle a message. 
(U)nshuffle a message. 
(Q)uit program. 
Choose a option to continue: 

Answer 1

你的問題是這樣的一行：

while x != 'q' or 'Q' : 

的問題是，Q本身總是返回True，所以表達將永遠是真實的。嘗試改變符合：

while x != 'q' and x != 'Q' : 

Answer 2

x != 'q' or 'Q'被處理爲(x != 'q') or 'Q'，和「Q」始終是真實的。

這將更好的是： x not in 'qQ'或x.lower() != 'q'