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| -rw-r--r-- | Doc/library/collections.rst | 32 |
1 files changed, 21 insertions, 11 deletions
diff --git a/Doc/library/collections.rst b/Doc/library/collections.rst index 0ed51bf..13a92c4 100644 --- a/Doc/library/collections.rst +++ b/Doc/library/collections.rst @@ -258,24 +258,34 @@ For example:: >>> c['h'] # four 'h' in which, witch, and watch 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>`_ - in the Wikipedia +**References**: - `Bag <http://www.gnu.org/software/smalltalk/manual-base/html_node/Bag.html>`_ - a Smalltalk class + * Wikipedia entry for `Multisets <http://en.wikipedia.org/wiki/Multiset>`_ - `C++ multisets <http://www.demo2s.com/Tutorial/Cpp/0380__set-multiset/Catalog0380__set-multiset.htm>`_ - a tutorial with standalone examples + * `Bag class <http://www.gnu.org/software/smalltalk/manual-base/html_node/Bag.html>`_ + in Smalltalk - `Bag class <http://code.activestate.com/recipes/259174/>`_ - an early Python recipe + * `C++ multisets <http://www.demo2s.com/Tutorial/Cpp/0380__set-multiset/Catalog0380__set-multiset.htm>`_ + 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, - Section 4.6.3, Exercise 19. + Section 4.6.3, Exercise 19 .. _deque-objects: |