Learn How to Work with Numbers and Strings by Implementing the Luhn Algorithm - Step 33

Python
1

Tell us what’s happening:

I feel like I’m doing exactly what I’m being asked but it’s not approving my code. Is there something wrong or is this a bug?

Your code so far

def verify_card_number(card_number):
    sum_of_odd_digits = 0
    card_number_reversed = card_number[::-1]
    odd_digits = card_number_reversed[::2]

    for digit in odd_digits:
        sum_of_odd_digits += int(digit)

    sum_of_even_digits = 0
    even_digits = card_number_reversed[1::2]
    for digit in even_digits:
        number = int(digit) * 2
        if number >= 10:
            number = (number // 10) + (number % 10)
        sum_of_even_digits += number
    total = sum_of_odd_digits + sum_of_even_digits
    print(total)
    return total % 10 == 0

/* User Editable Region */

def main():
    card_number = '4111-1111-4555-1142'
    card_translation = str.maketrans({'-': '', ' ': ''})
    translated_card_number = card_number.translate(card_translation)

    if verify_card_number(translated_card_number) is True:
        print('VALID!')
    else: 
        print('INVALID!')

/* User Editable Region */


main()

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Challenge Information:

Learn How to Work with Numbers and Strings by Implementing the Luhn Algorithm - Step 33

2

Can you give us more information? What’s the hint given?

This comparison is probably more complicated than it needs to be since that function returns true or false.

1 Like
3

These are the step instructions:
Adjust the verify_card_number call such that if it returns True , print VALID! to the console. Otherwise, print INVALID! .

And this is the hint:
You should have if verify_card_number(translated_card_number): within the main function.

1 Like
4

Ah. I mean, you don’t have that literal line of code. Your line is more complicated than that.

1 Like
5

Oh I see. Alright I changed that and now the hint changed to " You should have print("INVALID!") within the else clause."

Again, it seems to me that I have done exactly that, and I even tried moving the print to the same line as else.

6

What’s the updated code?

7 
if verify_card_number(translated_card_number):
    print('VALID!')
else: 
    print('INVALID!')
2 Likes
8

Oh, rude. The test doesn’t like the extra whitespace after your :

8 Likes
9

Omg :smiling_face_with_tear: Thank you so much!

10

I got stuck as well in this problem, I checked my code 10x and then I gave up trying I ended up here thanks I see your question I noticed right away I forgot to include ‘’" for the strings (VALID! & INVALID).