luhn.py

import random
first_6=400000 # IIN For Banking Industry(6 digits)
def luhn():
    global first_6  
    card_no = [int(i) for i in str(first_6)]  # To find the checksum digit on
    card_num = [int(i) for i in str(first_6)]  # Actual account number
    seventh_15 = random.sample(range(9), 9)  # Acc no (9 digits)
    for i in seventh_15:
        card_no.append(i)
        card_num.append(i)
    for t in range(0, 15, 2):  # odd position digits
        card_no[t] = card_no[t] * 2
    for i in range(len(card_no)):
        if card_no[i] > 9:  # deduct 9 from numbers greater than 9
            card_no[i] -= 9
    s = sum(card_no)
    mod = s % 10
    check_sum = 0 if mod == 0 else (10 - mod)
    card_num.append(check_sum)
    card_num = [str(i) for i in card_num]
    return ''.join(card_num)


print(luhn())