Credit Card 16-digit Random Number Generator

credit_card_16_digit_random_generator.py

# This method generates a 16 digit random credit card number. 
# If 'secure' flag is True, One of the four digits of every four digits, is replaced by a random Upper case letter.
import random

def generate_random_num(secure=False):
  random.seed()

  credit_card_num = []

  for i in range(4):
    # Generate a 4-digit random number
    four_digit_rand_num = [random.randint(1,9) for i in range(4)]
    #print four_digit_rand_num
    number = four_digit_rand_num
    
    if secure:      
      # Generate a random upper case letter
      upper_case_letters = map(chr, range(65, 91))
      letter = random.choice(upper_case_letters)
      #print letter
            
      # Generate a random position
      position = random.randint(0,3)
      #print position
            
      # Replace position
      number = four_digit_rand_num[:position]
      number.append(letter)
      number = number + four_digit_rand_num[position+1:]
      #print number
    
    number_str = ''.join(str(e) for e in number)
    #print number_str
    credit_card_num.append(number_str)
          
  return credit_card_num
  
print generate_random_num()