Learn String Manipulation by Building a Cipher - Step 61

Python
1

Tell us what’s happening:

The task is “use the addition assignment operator to increment key_index”. My answer was, ’ key_char += key_index’ and ‘key_index += key_char’.
Help, where did I got it wrong?

Your code so far


text = 'Hello Zaira'
custom_key = 'python'

def vigenere(message, key):
    key_index = 0
    alphabet = 'abcdefghijklmnopqrstuvwxyz'
    encrypted_text = ''

    for char in message.lower():

# User Editable Region

        # Append space to the message
        if char == ' ':
            encrypted_text += char
        else:
            key_char = key[key_index % len(key)]
            key_char += key_index


# User Editable Region

            index = alphabet.find(char)
            new_index = (index + offset) % len(alphabet)
            encrypted_text += alphabet[new_index]
    print('plain text:', message)
    print('encrypted text:', encrypted_text)

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Challenge Information:

Learn String Manipulation by Building a Cipher - Step 61

2

Hi there and welcome to our community!

use the addition assignment operator to increment key_index by one.

This line of code does not add 1 to key_index:

1 Like
3

Hello, thanks for the reply! Sorry, still very new to python but I thought addition assignment operator is ‘+=’? Or it’s “key_index += key_char”? But I tried that so that can’t be right, did I miss something else entirely?

4

how is that increasing by one?

use the addition assignment operator to increment key_index by one.

the instructions specifically ask to increase by one.

1 Like
5

It appears you confused the key_index variable for key_char. Key_index was already declared in line 6 (key_index = 0). That’s what you need to increment by one.

If I have a variable for example:
ring_index = 0
print(ring_index) # prints out 0
ring_index += 1 # Increments ring_index by 1.
print(ring_index) # prints out 1
ring_index += 1 # Increments ring_index by 1.
print(ring_index) # prints out 2

Apply this example to your code.

2 Likes
6

The previous example of additional operator got me confused, finally caught up to the fact that I actually need to add that value into the variable. Thank you!

1 Like
7

That is a very thorough explanation and I’m really grateful for that. I was very slow in understanding it but I finally got the answer right thank you!

8

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