Generate X random IBANs for Dutch bank ABN

randomIBANs.py

#!/usr/bin/env python

import sys
import random

def main():
    try:
        count = int(sys.argv[1])
        if count <= 0:
            raise ValueError
    except (IndexError, ValueError):
        count = 1

    ibans = get_random_ibans(count)
    for iban in ibans:
        print iban

    print ''
    iban_count = len(ibans)
    print iban_count, 'ibans' if iban_count != 1 else 'iban'

def get_random_ibans(count=10, ibans=[]):
    iban = try_iban()
    if not iban in ibans:
        ibans.append(iban)

    if len(ibans) == count:
        return ibans

    return get_random_ibans(count, ibans)

def try_iban():
    A = get_letter_number('A')
    B = get_letter_number('B')
    L = get_letter_number('L')
    N = get_letter_number('N')
    rand = random.randint(1, 999999999)

    sequence = int(list_to_string([
        A, B, N, A,
        format(rand, '010'),
        N, L,
        '00',
    ]))

    control_number = 98 - (sequence % 97)

    return list_to_string([
        'NL',
        format(control_number, '02'),
        'ABNA',
        format(rand, '010'),
    ])

def get_letter_number(letter):
    number = ord(letter) - 55
    return format(number, '02')

def list_to_string(ls=[]):
    return ''.join(map(str, ls))

if __name__ == "__main__":
    main()