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Minor documentation tweaks and simpler update() example.

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Raymond Hettinger 2009-01-13 03:49:43 +00:00
parent 5a0c864045
commit 8278385a05
1 changed files with 11 additions and 14 deletions
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Doc/library/collections.rst
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@ -175,7 +175,7 @@ For example::
[('the', 1143), ('and', 966), ('to', 762), ('of', 669), ('i', 631), [('the', 1143), ('and', 966), ('to', 762), ('of', 669), ('i', 631),
('you', 554), ('a', 546), ('my', 514), ('hamlet', 471), ('in', 451)] ('you', 554), ('a', 546), ('my', 514), ('hamlet', 471), ('in', 451)]
.. class:: Counter([iterable]) .. class:: Counter([iterable-or-mapping])
A :class:`Counter` is a :class:`dict` subclass for counting hashable items. A :class:`Counter` is a :class:`dict` subclass for counting hashable items.
It is an unordered collection where elements are stored as dictionary keys It is an unordered collection where elements are stored as dictionary keys
@ -183,8 +183,8 @@ For example::
any integer value including zero or negative counts. The :class:`Counter` any integer value including zero or negative counts. The :class:`Counter`
class is similar to bags or multisets in other languages. class is similar to bags or multisets in other languages.
Elements are counted from the *iterable* if given. Also, the counts Elements are counted from an *iterable* or initialized from another
can be initialized from another mapping of elements to their counts:: *mapping* (or counter)::
>>> c = Counter() # a new, empty counter >>> c = Counter() # a new, empty counter
>>> c = Counter('gallahad') # a new counter from an iterable >>> c = Counter('gallahad') # a new counter from an iterable
@ -244,21 +244,18 @@ For example::
There is no equivalent class method for :class:`Counter` objects. There is no equivalent class method for :class:`Counter` objects.
Raises a :exc:`NotImplementedError` when called. Raises a :exc:`NotImplementedError` when called.
.. method:: update(iterable) .. method:: update([iterable-or-mapping])
Like :meth:`dict.update` but adds-in counts instead of replacing them. Like :meth:`dict.update` but adds-in counts instead of replacing them.
Elements are counted from the *iterable* if given. Also, the counts Elements are counted from an *iterable* or added-in from another
can be taken from another counter or mapping of elements to their *mapping* (or counter)::
counts::
>>> c = Counter('which') # count letters in a word >>> c = Counter('which')
>>> d = Counter('witch') # count letters in another word >>> c.update('witch') # add elements from another iterable
>>> c.update(d) # add counts from d to those in c >>> d = Counter('watch')
>>> c['h'] # count of 'h' is now three >>> c.update(d) # add elements from another counter
3 >>> c['h'] # four 'h' in which, witch, and watch
>>> c.update('watch') # add in letters from another word
>>> c['h'] # count of 'h' is now four
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