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

Python
1

Tell us what’s happening:

still having trouble. I got where it would say that i need to change the card_number bact to something valid.

Your code so far


# User Editable Region

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

def main():
    card_number = '4111-1111-45551142'
    card_translation = str.maketrans({'-': '', ' ': ''})
    translated_card_number = card_number.translate(card_translation)

    if verify_card_number(translated_card_number):
        pass

main()

# User Editable Region

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Challenge Information:

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

2

You’ll need to change the number.

Did you change it recently? Do you remember what it was? You could go back a step.

Do you know what constitutes a valid number?

You could even try randomly changing digits of the number until it comes up as valid. You’ve just written a program that tells you if the number is valid or not

3

that was what the number was i have it written down

4

Is it valid according to the program?

5

no, It does not say that

6

Keep changing the last digit until it’s valid.

7

ok, I did that and this is my code now

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

    if verify_card_number(translated_card_number):
        pass

main()
8

I’ve edited your code for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.

You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.

Pre-formatted-text
Pre-formatted-text1356×380 401 KB

See this post to find the backtick on your keyboard.
Note: Backticks (`) are not single quotes (').

9

Ok, and do you have a question about anything?

Do you get any hints or test feedback?

10

oh ok thanks for that i didn’t kow