strings.credit_card_validator
=============================

.. py:module:: strings.credit_card_validator

.. autoapi-nested-parse::

   Functions for testing the validity of credit card numbers.

   https://en.wikipedia.org/wiki/Luhn_algorithm



Functions
---------

.. autoapisummary::

   strings.credit_card_validator.luhn_validation
   strings.credit_card_validator.validate_credit_card_number
   strings.credit_card_validator.validate_initial_digits


Module Contents
---------------

.. py:function:: luhn_validation(credit_card_number: str) -> bool

   Function to luhn algorithm validation for a given credit card number.
   >>> luhn_validation('4111111111111111')
   True
   >>> luhn_validation('36111111111111')
   True
   >>> luhn_validation('41111111111111')
   False


.. py:function:: validate_credit_card_number(credit_card_number: str) -> bool

   Function to validate the given credit card number.
   >>> validate_credit_card_number('4111111111111111')
   4111111111111111 is a valid credit card number.
   True
   >>> validate_credit_card_number('helloworld$')
   helloworld$ is an invalid credit card number because it has nonnumerical characters.
   False
   >>> validate_credit_card_number('32323')
   32323 is an invalid credit card number because of its length.
   False
   >>> validate_credit_card_number('32323323233232332323')
   32323323233232332323 is an invalid credit card number because of its length.
   False
   >>> validate_credit_card_number('36111111111111')
   36111111111111 is an invalid credit card number because of its first two digits.
   False
   >>> validate_credit_card_number('41111111111111')
   41111111111111 is an invalid credit card number because it fails the Luhn check.
   False


.. py:function:: validate_initial_digits(credit_card_number: str) -> bool

   Function to validate initial digits of a given credit card number.
   >>> valid = "4111111111111111 41111111111111 34 35 37 412345 523456 634567"
   >>> all(validate_initial_digits(cc) for cc in valid.split())
   True
   >>> invalid = "14 25 76 32323 36111111111111"
   >>> all(validate_initial_digits(cc) is False for cc in invalid.split())
   True