largest number

"""
Write a function that given a list of non negative integers, arranges them such that they form the largest possible number. For example, given [50, 2, 1, 9], the largest formed number is 95021.

You application should be run from the command line using a single command. For example:

  # $ python ./largest.py 100 3 67 9
  # $ sbt "run 100 3 67 9"
"""
#!/usr/bin/env python
 
import sys
 
 
def generate_largest_integer(integer_list, max_length):
    """Generates the largest int based on an int list &
    the length of the largest str(int) in the list"""
    integer_tuple_list = []  # array of tuples
    for integer in integer_list:  # 2nd item in tuple is left justified string with 9's up to max length
        integer_tuple_list.append((integer, integer.ljust(max_length, '9')))
    integer_tuple_list.sort(key=lambda x: x[1], reverse=True)  # Sort the list by 2nd (mask) value
    new_list = [seq[0] for seq in integer_tuple_list]
    print ''.join(new_list)
 
 
def main():
    integer_list = []
    args = sys.argv[1:]
    if len(args) == 0:
        print "Sorry no positive integers passed."
        print "usage: generate_largest.py positive_integer [N_positive_integers ...]"
    else:
        max_length = 0
        for arg in args:
            if arg.isdigit() and int(arg) > 0:  # Validate positive integers
                max_length = max(max_length, len(arg))  # Get max arg length
                integer_list.append(arg)
            else:
                raise Exception("Sorry only positive integers should be passed.")
        generate_largest_integer(integer_list, max_length)
 
if __name__ == '__main__':
    main()