perofrming caesarcipher for a string using shift

from string import ascii_lowercase as alphabet1
from string import ascii_uppercase as alphabet2

import letter as letter



def cipher(user_input, shift):
    cipher1 = {char: alphabet1[(i + shift) % 26] for i, char in enumerate(alphabet1)}
    cipher2 = {char: alphabet2[(i + shift) % 26] for i, char in enumerate(alphabet2)}
    
    caesar_cipher = ""
    
    for letter in user_input:
        caesar_cipher += cipher1.get(letter, letter)
    else:
        caesar_cipher += cipher2.get(letter, letter)
    return caesar_cipher


if __name__ == "__main__":
    
    user_input = input("Enter the String: ")
    
    shift = int(input("Enter shift: "))
    
    print("Caesar Cipher: " + cipher(user_input, shift))

I am performing Caeser cipher for both upper case and lower case characters. But the result i开发者_StackOverflow社区s not correct. cipher1 is for lowercase and cipher 2 is for upper case. I have defined it in a function. And called it in main method the result obtained for lower case is:

Enter the String: abc
Enter shift: 2
Caesar Cipher: cdec

it should be cde

The result obtained for upper case is:

Enter the String: ABC
Enter shift: 2
Caesar Cipher: ABCE

It should be CDE

Check whether each letter is upper or lower case then use the corresponding cipher.

    ...
    
    for letter in user_input:
        cipher = cipher1 if letter in cipher1 else cipher2
        print(cipher[letter])

c
D
e

When the iterator is exhausted, the suite in the else clause, if present, is executed, and the loop terminates.

Your else clause was always executing.

For loop

from string import ascii_lowercase as alphabet1 from string import ascii_uppercase as alphabet2

import letter as letter

def cipher(user_input, shift): cipher1 = {char: alphabet1[(i + shift) % 26] for i, char in enumerate(alphabet1)} cipher2 = {char: alphabet2[(i + shift) % 26] for i, char in enumerate(alphabet2)}

caesar_cipher = ""

for letter in user_input:
    caesar_cipher += cipher1.get(letter, letter)
else:
    caesar_cipher += cipher2.get(letter, letter)
return caesar_cipher

if name == "main":

user_input = input("Enter the String: ")

shift = int(input("Enter shift: "))

print("Caesar Cipher: " + cipher(user_input, shift))