Sort a list to form the largest possible number

Question

I am trying to write a function that given a list of non negative integers, arranges them such that they form the largest possible number.

For example, given

Answer 1

I hope I'm not varying too much on this. My input is cast as a list of strings. I generate the list of permutations, creating a list of lists, and then sort the sublists from least to greatest. Finally, I take the last element of the sorted list.

import itertools

digits = ['50', '2', '1', '9']
perms = itertools.permutations(digits)
sorted_numlist = sorted(perms)
print sorted_numlist[-1]

If you'd rather have the number itself rather than the list of elements...

import itertools

digits = ['11', '68', '4', '12']
perms = itertools.permutations(digits)
numlist = []
for sublist in perms:
    permutated_num = "".join(sublist)
    numlist.append(int(permutated_num))

sorted_numlist = sorted(numlist)
print sorted_numlist[-1]

That second one actually also serves to show the the first is properly sorting on lists.

I'm pretty new with Python and would appreciate comments/improvements.