Counter

Defining a Counter

  • A Counter is a dict subclass for counting hashable objects

  • Specifically, it is a dictionary where:

    • The keys represent the elements
    • The values represent counts
  • The counts are allowed to be any integer

Creating a Counter

>>> from collections import Counter
>>> c = Counter([1,2,3,1,3,1])
>>> print(c)
Counter({1: 3, 3: 2, 2: 1})

Accessing a Counter

>>> from collections import Counter
>>> c = Counter([1,2,3,1,3,1])
>>> print(c[1])
3

Accessing the 3 Most Common

>>> from collections import Counter
>>> c = Counter('abracadabra')
>>> print(c.most_common(3))
[('a', 5), ('b', 2), ('r', 2)]

Accessing the 2 Least Common

>>> from collections import Counter
>>> c = Counter('abracadabra')
print(c.most_common()[:-3:-1])
[('d', 1), ('c', 1)]

References

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