Vigenere Cipher Incredibly Confused

Question

ive been stuck on this for hours now. I've been trying to encrypt a preset message with a preset vigenere key. so that the name lets say 'bob' shifts by the key 'abc' it shifts the word bob by the ascii values 'abc'.

I have this code right now but it isn't printing anything whatsoever and i'm incredibly confused on how to do this.

def vigenere(key, letter):

    keyVal = ord(key)
    letterVal = ord(letter)

    keyVal = keyVal - 97

    letterVal = keyVal + letterVal

    if letterVal >= ord("z"):
        letterVal = letterVal - 26

        print letterVal

Answer 1

You have to do that in loop for a string, like I did below:

def vigenere(key, letter):

    letterChar = ""
    for i in range(len(letter)):
        keyVal = ord(key)
        letterVal = ord(letter[i])
        keyVal = keyVal - 97
        letterChar += chr(keyVal + letterVal)
        if letterVal >= ord('z'):
            letterVal = letterVal - 26

    print letterChar


vigenere('c', "pop")

It returns:

rqr