Encrypts or decrypts a message using the caesar cipher algorithm.

caesar_cipher.py

import string

list_of_alphabets_and_digits = [
    string.ascii_lowercase,
    string.ascii_uppercase,
    string.digits,
]


def shift(alphabets_and_digits_to_shift: str, key_to_shift_by: int) -> str:
    """
    Shift any digits and alphabets that are passed in.
    """
    return (
        alphabets_and_digits_to_shift[key_to_shift_by:]
        + alphabets_and_digits_to_shift[:key_to_shift_by]
    )


def encrypt_or_decrypt_text(
    message: str, key: int, alphabets_and_digits: list[str], decrypt_or_encrypt: bool
) -> str:
    """
    This function encrypts or decrypts a text that has been passed in
    and returns the encrypted / decrypted text.
    """

    shifted_alphabets_and_digits = [
        shift(value, key) for value in alphabets_and_digits
    ]  # Call the shift function with alphabets_and_digits using a list comprehension

    # turn characters in the list into a string
    joined_alphabets_and_digits = "".join(alphabets_and_digits)
    joined_shifted_alphabets_and_digits = "".join(shifted_alphabets_and_digits)

    if decrypt_or_encrypt is True:
        mapping_table = str.maketrans(
            joined_alphabets_and_digits, joined_shifted_alphabets_and_digits
        )  # Create a mapping table
    else:
        mapping_table = str.maketrans(
            joined_shifted_alphabets_and_digits, joined_alphabets_and_digits
        )

    return message.translate(
        mapping_table
    )  # Use the mapping table to replace characters in
    # the original message with the shifted characters


print("Heya. Welcome to the Caesar Cipher Program\n")

choose_decryption_or_encryption = input(
    "Please type yes if you'll like to like encrypt a message or no if you'll like to decrypt a message: \n"
).lower()

choose_decryption_or_encryption = (
    True if choose_decryption_or_encryption == "yes" else False
)

message = input("\nPlease type the message you'll like to encrypt_or_decrypt\n")

key = int(
    input(
        "\nPlease type the key you'll like to encrypt_or_decrypt the message with.\n"
        "This should be a positive integer between the range of 0 to 25. \n"
    )
)

if __name__ == "__main__":
    print(f"\n{encrypt_or_decrypt_text(message, key, list_of_alphabets_and_digits, choose_decryption_or_encryption)}")