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

Python
1

Tell us what’s happening:

which card_number shall I change? I changed the card N many times it didn’t work.
Simply I didn’t understand the project.

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 = '4111-1111-4555-1141'
    card_translation = str.maketrans({'-': '', ' ': ''})
    translated_card_number = card_number.translate(card_translation)

    if verify_card_number(translated_card_number):
        pass
    

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/131.0.0.0 Safari/537.36 Edg/131.0.0.0

Challenge Information:

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

2

this card_number is the one you need to change

3

Tell us what’s happening:

I did what I was told to do, but it still not passing the 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
    print(total)
    return total % 10 == 0

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

    verify_card_number(translated_card_number)
       
    

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/131.0.0.0 Safari/537.36 Edg/131.0.0.0

Challenge Information:

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

4

you removed too many things. Reset the step, find the verify_card_number and remove the print call from inside that, not from inside main.

5

Tell us what’s happening:

I doesn’t seem to work, even following the instructions!

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
    print(total)
    return total % 10 == 0

def main():
    card_number = '4111-1111-4556-1141'
    card_translation = str.maketrans({'-': '', ' ': ''})
    translated_card_number = card_number.translate(card_translation)

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

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/131.0.0.0 Safari/537.36 Edg/131.0.0.0

Challenge Information:

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

6

Do not open duplicate topics.

Did you reset the step?

Which part of your code is the verify_card_number function?

Do not delete anything from the main function.

7

Thanks ILM, it worked. Thanks to you :+1:

8

card_number = ‘4111-1111-4555-1141’ the problem is that there was a 2 at the end which they removed from the last step (ie) change the card number to somthing ‘INVALID!’ .
number should be changed to this
card_number = ‘4111-1111-4555-1142’

9

if that was the only issue it would have been much shorter