Learn String Manipulation by Building a Cipher - Step 75

Tell us what’s happening:

i did what the instructions told me to do, add .isalpha() to char, but i keep getting errors. what am i doing wrong?
(i know there was a similar previous post saying an indentation error is what occurred, but i cannot figure out if/where that’s occurring)

Your code so far

text = 'Hello Zaira!'
custom_key = 'python'

def vigenere(message, key, direction=1):
    key_index = 0
    alphabet = 'abcdefghijklmnopqrstuvwxyz'
    final_message = ''

    for char in message.lower():

/* User Editable Region */

        # Append space to the message
        if char.isalpha() == ' ':
            final_message += char

/* User Editable Region */

            # Find the right key character to encode/decode
            key_char = key[key_index % len(key)]
            key_index += 1

            # Define the offset and the encrypted/decrypted letter
            offset = alphabet.index(key_char)
            index = alphabet.find(char)
            new_index = (index + offset*direction) % len(alphabet)
            final_message += alphabet[new_index]
    return final_message
encryption = vigenere(text, custom_key)
decryption = vigenere(encryption, custom_key, -1)

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Learn String Manipulation by Building a Cipher - Step 75

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Hello Yuh,

islapha() returns True or False depending on if char is a letter or not. So essentially you are now comparing that True or False against an empty space.

All you need to know is if char is a letter, if it is, you add it to the final_message variable.


Thank you, I have been experiencing the same difficulty!!

1 Like

thank you so much, i got it now!

1 Like

Hasn’t worked for me

We can’t see your code so it would be hard to help you.
I would advise making your own topic and showing us what you’ve been trying.