Classe « Counter »

Informations générales

Héritage

builtins.object
    builtins.dict
        Counter

Définition

class Counter(builtins.dict):

help(Counter)

Dict subclass for counting hashable items.  Sometimes called a bag
or multiset.  Elements are stored as dictionary keys and their counts
are stored as dictionary values.

>>> c = Counter('abcdeabcdabcaba')  # count elements from a string

>>> c.most_common(3)                # three most common elements
[('a', 5), ('b', 4), ('c', 3)]
>>> sorted(c)                       # list all unique elements
['a', 'b', 'c', 'd', 'e']
>>> ''.join(sorted(c.elements()))   # list elements with repetitions
'aaaaabbbbcccdde'
>>> sum(c.values())                 # total of all counts
15

>>> c['a']                          # count of letter 'a'
5
>>> for elem in 'shazam':           # update counts from an iterable
...     c[elem] += 1                # by adding 1 to each element's count
>>> c['a']                          # now there are seven 'a'
7
>>> del c['b']                      # remove all 'b'
>>> c['b']                          # now there are zero 'b'
0

>>> d = Counter('simsalabim')       # make another counter
>>> c.update(d)                     # add in the second counter
>>> c['a']                          # now there are nine 'a'
9

>>> c.clear()                       # empty the counter
>>> c
Counter()

Note:  If a count is set to zero or reduced to zero, it will remain
in the counter until the entry is deleted or the counter is cleared:

>>> c = Counter('aaabbc')
>>> c['b'] -= 2                     # reduce the count of 'b' by two
>>> c.most_common()                 # 'b' is still in, but its count is zero
[('a', 3), ('c', 1), ('b', 0)]

Constructeur(s)

Signature du constructeur	Description
__init__(self, iterable=None, /, **kwds)	Create a new, empty Counter object. And if given, count elements _{[extrait de __init__.__doc__]}

Liste des opérateurs

Signature de l'opérateur	Description
__add__(self, other)	Add counts from two counters. _{[extrait de __add__.__doc__]}
__and__(self, other)	Intersection is the minimum of corresponding counts. _{[extrait de __and__.__doc__]}
__delitem__(self, elem)	Like dict.__delitem__() but does not raise KeyError for missing values. _{[extrait de __delitem__.__doc__]}
__eq__(self, other)	True if all counts agree. Missing counts are treated as zero. _{[extrait de __eq__.__doc__]}
__ge__(self, other)	True if all counts in self are a superset of those in other. _{[extrait de __ge__.__doc__]}
__gt__(self, other)	True if all counts in self are a proper superset of those in other. _{[extrait de __gt__.__doc__]}
__iadd__(self, other)	Inplace add from another counter, keeping only positive counts. _{[extrait de __iadd__.__doc__]}
__iand__(self, other)	Inplace intersection is the minimum of corresponding counts. _{[extrait de __iand__.__doc__]}
__ior__(self, other)	Inplace union is the maximum of value from either counter. _{[extrait de __ior__.__doc__]}
__isub__(self, other)	Inplace subtract counter, but keep only results with positive counts. _{[extrait de __isub__.__doc__]}
__le__(self, other)	True if all counts in self are a subset of those in other. _{[extrait de __le__.__doc__]}
__lt__(self, other)	True if all counts in self are a proper subset of those in other. _{[extrait de __lt__.__doc__]}
__ne__(self, other)	True if any counts disagree. Missing counts are treated as zero. _{[extrait de __ne__.__doc__]}
__neg__(self)	Subtracts from an empty counter. Strips positive and zero counts, _{[extrait de __neg__.__doc__]}
__or__(self, other)	Union is the maximum of value in either of the input counters. _{[extrait de __or__.__doc__]}
__pos__(self)	Adds an empty counter, effectively stripping negative and zero counts _{[extrait de __pos__.__doc__]}
__sub__(self, other)	Subtract count, but keep only results with positive counts. _{[extrait de __sub__.__doc__]}

Opérateurs hérités de la classe dict

__contains__, __getitem__, __ror__, __setitem__

Liste des méthodes

Toutes les méthodes Méthodes d'instance Méthodes statiques

Signature de la méthode	Description
__class_getitem__(object)	See PEP 585 _{[extrait de __class_getitem__.__doc__]}
__missing__(self, key)	The count of elements not in the Counter is zero. _{[extrait de __missing__.__doc__]}
__reduce__(self)
__repr__(self)
copy(self)	Return a shallow copy. _{[extrait de copy.__doc__]}
elements(self)	Iterator over elements repeating each as many times as its count. _{[extrait de elements.__doc__]}
fromkeys(iterable, v=None)
most_common(self, n=None)	List the n most common elements and their counts from the most _{[extrait de most_common.__doc__]}
subtract(self, iterable=None, /, **kwds)	Like dict.update() but subtracts counts instead of replacing them. _{[extrait de subtract.__doc__]}
total(self)	Sum of the counts _{[extrait de total.__doc__]}
update(self, iterable=None, /, **kwds)	Like dict.update() but add counts instead of replacing them. _{[extrait de update.__doc__]}