Learn How to Work with Numbers and Strings by Implementing the Luhn Algorithm - Step 35

Python
1

Tell us what’s happening:

How is card_number changed to valid in the Luhn code?

Your code so far


# User Editable Region

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
    
    return total % 10 == 0

def main():
    card_number = '4111-1111-4555-11412'
    card_translation = str.maketrans({'-': '', ' ': ''})
    translated_card_number = card_number.translate(card_translation)

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

main()

# User Editable Region

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36

Challenge Information:

Learn How to Work with Numbers and Strings by Implementing the Luhn Algorithm - Step 35

2

Welcome to the forum @Galy

Try changing the value back to what it was in the previous step.

Happy coding

3

Hi @Galy you have to change the card number to ‘4111-1111-4555-1142’ . In other posts I see that people delete if statement and this is and error for approve this step. You’ve got it right.