Coding caesar's cipher

[drewbty]

Hi

I am starting off in python and as part of my learning I'm attempting to code a simple caeser's cipher.

I have figured out how to get this working if I don't have the get_offset as a function to call, but I would like to know how to do this as the ability to call functions is giving me headaches.

What I'm trying to achive:

1: program a function (get_offset) to input the shift of the caeser ciper, to be called once entering the string to encrypt/decrypt as per menu options 1 and 2.
2: have this function loop back to the shift int(input) whenever a number that isn't a digit is entered, or a digit is entered that is not between 1 and 94. I currently only have if statements there and those are not working also

1	shift = int(input('Please enter offset value (1 to 94): '))

3: additional question, I'm struggling to understand if in this case I should have my function as get_offset(shift): or get_offset(): and why either should be the case.

TIA

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def menuChoice():       print ('')     print ('Menu')     print ('')     print ('1. Encrypt string')     print ('2. Decrypt string')     print ('3. Brute force decryption')     print ('4. Quit')     print ('')       choice = input('What would you like to do (1,2,3,4)? ')       while choice != '1' and choice != '2' and choice != '3' and choice != '4':         print ('Invalid choice, please enter either 1, 2, 3 or 4.')         choice = input('\nWhat would you like to do (1,2,3,4)? ')           return choice   def get_offset():       shift = int(input('Please enter offset value (1 to 94): '))           if shift.isdigit == 0:         shift = int(input('Please enter offset value (1 to 94): '))     elif shift <0 or shift > 95:         shift = int(input('Please enter offset value (1 to 94): '))     else:         return shift       choice = menuChoice()   if choice == '1':     encrypt = input('Please enter string to encrypt: ')     shift = get_offset()     cipher = ''       for i in encrypt:         cipher += chr((ord(i) - 32 + shift) % 95 + 32)                   print ('\nEncrypted string:')     print (cipher)   elif choice == '2':     decrypt = input('Please enter string to decrypt: ')     shift = get_offset()     cipher = ''       for i in decrypt:         cipher += chr((ord(i) - 32 - shift) % 95 + 32)                   print ('\nDecrypted string:')     print (cipher)   elif choice == '3':     decrypt = input('Please enter string to decrypt: ')     brute_shift = 1     cipher = ''       for index in range(94):         for i in decrypt:             cipher += chr((ord(i) - 32 - brute_shift) % 95 + 32)         print ('Offset: ', brute_shift,'= Decrytped string: ', cipher)         brute_shift += 1         cipher = ''

Output:
Menu

1. Encrypt string
2. Decrypt string
3. Brute force decryption
4. Quit

What would you like to do (1,2,3,4)? 1
Please enter string to encrypt: one more time
Please enter offset value (1 to 94): 3[output]

Error:
Traceback (most recent call last):
  File "C:/Users/Angelica/Documents/caesercipher.py", line 44, in <module>
    shift = get_offset()
  File "C:/Users/Angelica/Documents/caesercipher.py", line 31, in get_offset
    if shift.isdigit == 0:
AttributeError: 'int' object has no attribute 'isdigit'

[pyzyx3qwerty]

Not .isdigit, use .isdigit().
Also, I do not think the way you use .isdigit() is correct. See this

[drewbty]

Thanks. My code was all completely wrong and I got it figured out, but the missing () was a good spot

My function became:

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def get_offset():     while True:         shift = input('Please enter offset value (1 to 94): ')         if shift.isdigit():             shift = int(shift)             if shift >=1 and shift <= 94:                 return shift

and to call the function later became

1	shift = get_offset()

[DPaul]

Maybe you also want to consider a small improvement:

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choices = (1,2,3,4) choice = 1 if choice in choices:     print("success")

Paul