Comment on Caesar Cipher Python Code by Cryptc.

Caesar Cipher Left Shift of 3 A more modern way to do this, which is also reasonably easy to read, is with string translations. These are high performance and flexible. You only have to build the mapping once and it will automatically iterate over each character when you translate it.

plainText = input("\nEnter your text:  ")
shift = int(input("How many places to shift:  "))
lowerAlpha = "abcdefghijklmnopqrstuvwxyz"
upperAlpha = lowerAlpha.upper()
numbers = "0123456789"
before = lowerAlpha + upperAlpha + numbers
after = lowerAlpha[shift:] + lowerAlpha[:shift] + \
    upperAlpha[shift:] + upperAlpha[:shift] + \
    numbers[shift:] + numbers[:shift]
translation = str.maketrans(before, after)
cipherText = plainText.translate(translation)
print("\nCoded Message:  {}".format(cipherText))
print("\nFrom:  {}".format(before))
print("  To:  {}\n".format(after))