Validate credit card data using Z Open Automation Utilities and Python

cc_check.py

# Import the Z Open Automation Utilities libraries we need
from zoautil_py import MVSCmd, Datasets
from zoautil_py.types import DDStatement

# Import datetime, needed so we can format the report
from datetime import datetime

# Import os, needed to get the environment variables
import os

import re

# Take the contents of this data set and read it into cc_contents
cc_contents = Datasets.read("MTM2020.PUBLIC.CUST16")

USERID = os.getenv("USER")
output_dataset = USERID + ".OUTPUT.CCINVALD"
# Delete the output dataset if it already exists
if Datasets.exists(output_dataset):
    Datasets.delete(output_dataset)
# Use this line to create a new SEQUENTIAL DATA SET with the name of output_dataset
# (hint: https://www.ibm.com/support/knowledgecenter/SSKFYE_1.0.1/python_doc_zoautil/api/datasets.html?view=embed)


def luhn(card_number):
    def digits_of(n):
        return [int(d) for d in str(n)]

    digits = digits_of(card_number)
    odd_digits = digits[-1::-2]
    even_digits = digits[-2::-2]
    checksum = 0
    checksum += sum(odd_digits)
    for d in even_digits:
        checksum += sum(digits_of(d * 2))
    return checksum % 10


# A function that checks to see if the number passed to it is even. Returns True or False (Boolean)
# def is_even(num_to_check):  # this is a function. num_to_check is what gets sent to it
#     if (num_to_check % 2) == 0:  # a simple check to see if num_to_check is even.
#         result = True  # We set result to True
#         return result  # and then return it.
#     else:  # if it isn't
#         result = False  # set return to False
#         return result  # and return that.


cc_list = cc_contents.splitlines()  # take that giant string and turn it into a List
invalid_cc_list = []  # A second list to hold invalid entries
for cc_line in cc_list:  # do everything here for every item in that List
    # cc_digits = int(
    #     cc_line[8:16]
    # )  # Just grabbing some digits. Not a full CC number (HINT!)
    # if is_even(cc_digits):  # If the card number is valid
    #     invalid_cc_list.append(cc_line)
    credit_card_number = re.findall("^%B([0-9]{1,19})", cc_line.split(" ")[0])[0]
    if luhn(credit_card_number):
        invalid_cc_list.append(cc_line)


# The Report-Writing Part
#
# NOTE: DON'T USE APPEND FOR MULTIPLE LINES.
#       IT WILL BE SLOW
#       INSTEAD, THROW EVERYTHING INTO A VARIABLE
#       AND WRITE THAT OUT ONCE, LIKE THIS.
#
#       TRUST US ON THIS.
#
#       YOU SHOULD BE ABLE TO USE THE CODE BELOW, ONLY HAVING TO ADD
#       A LINE TO WRITE OUT THE FINAL report_output TO YOUR output_dataset
#       REMEMBER, THE REPORT NEEDS TO HAVE THE DATETIME STRING IN IT ABOVE THE DATA
#
now = datetime.now()
dt_string = now.strftime("%d/%m/%Y %H:%M:%S")
report_output = "\n".join(invalid_cc_list)
report_output = "INVALID CREDIT CARD REPORT FOR " + dt_string + "\n\n" + report_output
print(report_output)  # Print it out to the screen.
# When you're ready to write your report out to file, uncomment that last line
Datasets.create(output_dataset, "SEQ")
Datasets.write(output_dataset, report_output)