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Add table of idioms/patterns for using Counter objects.

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Improve the appearance and flow of the References section -- it used
to have a box around it that wasn't distinct from the preceding code
boxes and it had a weird bolding pattern and hanging indents that
made the section disproportionately large.
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Raymond Hettinger 2009-01-13 08:38:14 +00:00
parent dd958e0d28
commit fbcf749479
1 changed files with 21 additions and 11 deletions
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32
Doc/library/collections.rst
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@ -258,24 +258,34 @@ For example::
>>> c['h'] # four 'h' in which, witch, and watch >>> c['h'] # four 'h' in which, witch, and watch
4 4
Common patterns for working with :class:`Counter` objects::
.. seealso:: sum(c.values()) # total of all counts
c.clear() # reset all counts
list(c) # list unique elements
set(c) # convert to a set
dict(c) # convert to a regular dictionary
c.items() # convert to a list of (elem, cnt) pairs
Counter(dict(list_of_pairs)) # convert from a list of (elem, cnt) pairs
c.most_common()[-n:] # n least common elements
`Multisets <http://en.wikipedia.org/wiki/Multiset>`_ **References**:
in the Wikipedia
`Bag <http://www.gnu.org/software/smalltalk/manual-base/html_node/Bag.html>`_ * Wikipedia entry for `Multisets <http://en.wikipedia.org/wiki/Multiset>`_
a Smalltalk class
`C++ multisets <http://www.demo2s.com/Tutorial/Cpp/0380__set-multiset/Catalog0380__set-multiset.htm>`_ * `Bag class <http://www.gnu.org/software/smalltalk/manual-base/html_node/Bag.html>`_
a tutorial with standalone examples in Smalltalk
`Bag class <http://code.activestate.com/recipes/259174/>`_ * `C++ multisets <http://www.demo2s.com/Tutorial/Cpp/0380__set-multiset/Catalog0380__set-multiset.htm>`_
an early Python recipe tutorial with standalone examples
Use cases for multisets and mathematical operations on multisets. * An early Python `Bag <http://code.activestate.com/recipes/259174/>`_ recipe
for Python 2.4 and a `Counter <http://code.activestate.com/recipes/576611/>`_
comformant recipe for Python 2.5 and later
* Use cases for multisets and mathematical operations on multisets.
Knuth, Donald. The Art of Computer Programming Volume II, Knuth, Donald. The Art of Computer Programming Volume II,
Section 4.6.3, Exercise 19. Section 4.6.3, Exercise 19
.. _deque-objects: .. _deque-objects: