Changes proposed by a client

Pete's comments:

I made 2 minor changes to the original:

I altered the check to the first 2 characters to explicitly test that they were A-Z alpha characters. (The original only checked that they were non-numeric)
I also removed the message regarding the preference for upper-case letters. Since the function converts to upper anyway, it seemed unnecessary to bother the tester with that.

I did not bother to test my suspicion, but I was concerned that the function would throw a traceback error if the tester had entered a non-alpha at the beginning of the ID and it was subsequently submitted to the .upper() method later in the function.

In general, I was delighted with the elegance of this solution to validating input from the tester.

Pete's changes:

def validate_id(some_id):
    # Basic checks: len == 7, first two chars letters,
    # all other chars are numbers

    if len(some_id) != 7:
        return False

    if not some_id[0].isalpha():
        return False

    if not some_id[1].isalpha():
        return False

    if not all([n.isdecimal() for n in some_id[2:6]]):
        return False

    # Convert ID to array of numbers, excluding check digit
    id_array = []
    id_array.append(ord(some_id[0].upper()))
    id_array.append(ord(some_id[1].upper()))
    id_array = id_array + list(some_id[2:6])

    # Use check digit algorithm to generate correct check digit
    check_digit_array = []

    for pos in range(len(id_array)):
        check_digit_array.append(int(id_array[pos]) * (pos+1))
    check_digit = sum(check_digit_array) % 10

    # Check correct check digit against entered ID
    if int(some_id[6]) != check_digit:
        return False

    return True

cc @sbouix

AMP-SCZ / subject-id-gen

Changes proposed by a client #5

Pete's comments:

Pete's changes: