Debug an ISBN Validator - Debug an ISBN Validator

Python
1

Tell us what’s happening:

I have no idea how to even start. It says I should fix the IndentationError, but when I run the code, it doesn’t even write that I have one.

Your code so far

def validate_isbn(isbn, length):
    if len(isbn, length) != length:
        print(f'ISBN-{length} code should be {length} digits long.')
        return
    main_digits = isbn[0:length]
    given_check_digit = isbn[length]
    main_digits_list = [int(digit) for digit in main_digits]
    # Calculate the check digit from other digits
    if length == 10:
        expected_check_digit = calculate_check_digit_10(main_digits_list)
    else:
        expected_check_digit = calculate_check_digit_13(main_digits_list)
    # Check if the given check digit matches with the calculated check digit
    if given_check_digit == expected_check_digit:
        print('Valid ISBN Code.')
    else:
        print('Invalid ISBN Code.')
def calculate_check_digit_10(main_digits_list):
    # Note: You don't have to fully understand the logic in this function.
    digits_sum = 0
    # Multiply each of the first 9 digits by its corresponding weight (10 to 2) and sum up the results
    for index, digit in enumerate(main_digits_list):
        digits_sum += digit * (10 - index)
    # Find the remainder of dividing the sum by 11, then subtract it from 11
    result = 11 - digits_sum % 11
    # The calculation result can range from 1 to 11.
    # If the result is 11, use 0.
    # If the result is 10, use upper case X.
    # Use the value as it is for other numbers.
    if result == 11:
        expected_check_digit = '0'
    elif result == 10:
        expected_check_digit = 'X'
    else:
        expected_check_digit = str(result)
    return expected_check_digit
def calculate_check_digit_13(main_digits_list):
    # Note: You don't have to fully understand the logic in this function.
    digits_sum = 0
    # Multiply each of the first 12 digits by 1 and 3 alternately (starting with 1), and sum up the results
    for index, digit in enumerate(main_digits_list):
        if index % 2 == 0:
            digits_sum += digit * 1
        else:
            digits_sum += digit * 3
    # Find the remainder of dividing the sum by 10, then subtract it from 10
    result = 10 - digits_sum % 10
    # The calculation result can range from 1 to 10.
    # If the result is 10, use 0.
    # Use the value as it is for other numbers.
    if result == 10:
        expected_check_digit = '0'
    else:
        expected_check_digit = str(result)
    return expected_check_digit
def main():
    user_input = input('Enter ISBN and length: ')
    values = user_input.split(',')
    isbn = values[0]
    length = int(values[1])
    if length == 10 or length == 13:
        validate_isbn(isbn, length)
        else:
            print('Length should be 10 or 13.')

#main()

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Challenge Information:

Debug an ISBN Validator - Debug an ISBN Validator

2

Hi @Mester,

In this lab, you will fix the existing code and make it function properly.

Traceback (most recent call last):
  File "main.py", line 63
    else:
    ^^^^
SyntaxError: invalid syntax

Start by fixing the syntax error shown in the console.

Then uncomment main() to test your code with the ISBN and lengths shown in the table.

Happy coding!

3

Thanks! Now the next step is “When the user inputs a value that is not a comma separated value, you should see the message Enter comma-separated values. in the console.”
But there is no such line in the code??

4

Indeed this line doesn’t exist, you have to write it. This is the point of the project : adding debugging to an already existing project. You have to add a feature that prevent user from writing not comma-separated values.