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Sync-up 3.1 docs with 2.7 for collections.Counter().

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Raymond Hettinger 2009-02-25 22:51:40 +00:00
parent 0f31e6db36
commit 72a95cc7b0
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13
Doc/library/collections.rst
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@ -236,13 +236,12 @@ Common patterns for working with :class:`Counter` objects::
c.most_common()[:-n:-1] # n least common elements
c += Counter() # remove zero and negative counts
Several multiset mathematical operations are provided for combining
:class:`Counter` objects. Multisets are like regular sets but are allowed to
contain repeated elements (with counts of one or more). Addition and
subtraction combine counters by adding or subtracting the counts of
corresponding elements. Intersection and union return the minimum and maximum
of corresponding counts. Each operation can accept inputs with signed counts,
but the output excludes results with counts less than one.
Several mathematical operations are provided for combining :class:`Counter`
objects to produce multisets (counters that have counts greater than zero).
Addition and subtraction combine counters by adding or subtracting the counts
of corresponding elements. Intersection and union return the minimum and
maximum of corresponding counts. Each operation can accept inputs with signed
counts, but the output will exclude results with counts of zero or less.
>>> c = Counter(a=3, b=1)
>>> d = Counter(a=1, b=2)