Python Projects
# How to Create Caesar Cipher Using Python
import string
import sys
# The word to be encoded shifts by 5 to the right, while the word to be decoded shifts by 5 to the left.
shift = 5
print(' Caesar Cipher '.center(40, '*'))
choices = ['e', 'd']
user_choice = input('Do you wish to [e]ncode, [d]ecode, or quit (any other letter)?: ').lower()
if user_choice not in choices:
print('Program closed.')
sys.exit()
word = input('Enter the word: ')
# ENCODING FUNCTION
def encode_words(words, shifts):
"""This encodes a word using Caesar cipher."""
# Variable for storing the encoded word.
encoded_word = ''
for i in words:
# Check for space and tab
if ord(i) == 32 or ord(i) == 9:
shifted_word = ord(i)
# Check for punctuations
elif i in string.punctuation:
shifted_word = ord(i)
# Check if the character is lowercase or uppercase
elif i.islower():
shifted_word = ord(i) + shifts
# Lowercase spans from 97 to 122 (decimal) on the ASCII table
# If the chars exceeds 122, we get the number it uses to exceed it and add to 96 (the character before a)
if shifted_word > 122:
shifted_word = (shifted_word - 122) + 96
else:
shifted_word = ord(i) + shifts
# Uppercase spans from 65 to 90 (decimal) on the ASCII table
# If the chars exceeds 90, we get the number it uses to exceed it and add to 64 (the character before A)
if shifted_word > 90:
shifted_word = (shifted_word - 90) + 64
encoded_word = encoded_word + chr(shifted_word)
print('Word:', word)
print('Encoded word:', encoded_word)
# DECODING FUNCTION
def decode_words(words, shifts):
"""This decodes a word using Caesar cipher"""
# Variable for storing the decoded word.
decoded_word = ''
for i in words:
# Check for space and tab
if ord(i) == 32 or ord(i) == 9:
shifted_word = ord(i)
# Check for punctuations
elif i in string.punctuation:
shifted_word = ord(i)
# Check if the character is lowercase or uppercase
elif i.islower():
shifted_word = ord(i) - shifts
# If the char is less 122, we get difference subtract from 123 (the character after z)
if shifted_word < 97:
shifted_word = (shifted_word - 97) + 123
else:
shifted_word = ord(i) - shifts
# If the char is less 65, we get difference and subtract from 91 (the character after Z)
if shifted_word < 65:
shifted_word = (shifted_word - 65) + 91
decoded_word = decoded_word + chr(shifted_word)
print('Word:', word)
print('Decoded word:', decoded_word)
def encode_decode(words, shifts, choice):
"""This checks if the users want to encode or decode, and calls the required function."""
if choice == 'e':
encode_words(words, shifts)
elif choice == 'd':
decode_words(words, shifts)
encode_decode(word, shift, user_choice)
OHIOLee