While Loop Fail - Caesar Cipher

Question

I'm having a problem where when I ask my program to quit out it prints like I ask it to, however shows my menu of options as well continuously.

So I'm getting this:

>>> 
(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:

Where I want it to display this if I choose 'q':

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

Here is my complete code, please explain why my menu is reprinting, did I make my while loop wrong, or is something out of place in my code?

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()

I want the program to display the menu after shuffling a message, or unshuffling a message, as well as at the beginning, but not after the user has asked to quit the program by choosing 'q'.

---

Edited code:

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()

New Output:

>>> ================================ 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: 

• Pyranja: In addition to the correct answers you could consider using a while x.lower() != 'q': ... else: print ('Goodbye') . That saves an if statement and expresses the intent more clearly in my opinion.

Answer 1

x != 'q' or 'Q' is being handled as (x != 'q') or 'Q', and 'Q' is always True.

It would better be: x not in 'qQ' or x.lower() != 'q'

• D Read: You are repeating yourself in the code, which is a bad habit. I suggest you do everything in a while True: loop, and if the user wants to quit, break. This sort of issue with 'while' loops comes up frequently.

Answer 2

Your problem is this line:

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

The problem is that Q itself will always return True, so the expression will always be true. Try changing the line with:

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

• Robert Montz: This helps but however if I shuffle a message, and then attempt to quit, the program stops without printing the quit message of "Goodbye!". Why's this?
• Martin Hallén: This is because the print("Goodbye!") comes before the while-loop. You can add if x == 'q' or x == 'Q': print("Goodbye!") to the bottom of the while loop.
• Robert Montz: I tryed to put it at the bottom of the while loop, however now it's reprinting the menu again.
• Robert Montz: I added my edited code to the original post at the bottom, as well as the output I'm now receiving.
• Martin Hallén: Make sure that it is inside the while loop, right after the input