Backport r68942: update powerset() recipe.
diff --git a/Doc/library/itertools.rst b/Doc/library/itertools.rst
index aef3f6a..dd998f6 100644
--- a/Doc/library/itertools.rst
+++ b/Doc/library/itertools.rst
@@ -673,11 +673,9 @@
nexts = cycle(islice(nexts, pending))
def powerset(iterable):
- "powerset('ab') --> set([]), set(['a']), set(['b']), set(['a', 'b'])"
- # Recipe credited to Eric Raymond
- pairs = [(2**i, x) for i, x in enumerate(iterable)]
- for n in xrange(2**len(pairs)):
- yield set(x for m, x in pairs if m&n)
+ "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))
def compress(data, selectors):
"compress('ABCDEF', [1,0,1,0,1,1]) --> A C E F"