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Power set: Difference between revisions
→Python: Standard documentation: Added.
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return p(l[1:]) + [[l[0]] + x for x in p(l[1:])]
</lang>
===Python: Standard documentation===
Pythons [http://docs.python.org/3/library/itertools.html?highlight=powerset#itertools-recipes documentation] has a method that produces the groupings, but not as sets:
<lang python>>>> from pprint import pprint as pp
>>> from itertools import chain, combinations
>>>
>>> def powerset(iterable):
"powerset([1,2,3]) --> () (1,) (2,) (3,) (1,2) (1,3) (2,3) (1,2,3)"
s = list(iterable)
return chain.from_iterable(combinations(s, r) for r in range(len(s)+1))
>>> pp(set(powerset({1,2,3,4})))
{(),
(1,),
(1, 2),
(1, 2, 3),
(1, 2, 3, 4),
(1, 2, 4),
(1, 3),
(1, 3, 4),
(1, 4),
(2,),
(2, 3),
(2, 3, 4),
(2, 4),
(3,),
(3, 4),
(4,)}
>>> </lang>
=={{header|Qi}}==
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