1 """Assorted useful combinatorics.
5 def xunique_combinations(items, n):
6 """Iterate through unordered, length `n` subsets of `items`.
8 >>> for c in xunique_combinations([1, 2, 3], 2):
16 for i in xrange(len(items)):
17 for cc in xunique_combinations(items[i+1:],n-1):