CODEWITHSUNDEEP
pythonlistpython-2.7counter
indecisivecoder
indecisivecoder

Reputation: 267

Using Counter with list of lists

How would I use the Counter in the collections library to convert a list of lists into a count of the number of times each word occurs overall?

E.g. [['a','b','a','c'], ['a','b','c','d']] -> {a:2, b:2, c:2, d:1}

i.e. a,b and c occur in both lists but d only occurs in one list.

Upvotes: 22

Views: 22339

Answers (3)

igorkf
igorkf

Reputation: 3565

from itertools import chain
from collections import Counter

seq = [['a','b','a','c'], ['a','b','c','d']]
c = Counter(chain(*seq))

print(c)
Counter({'a': 3, 'b': 2, 'c': 2, 'd': 1})

Upvotes: 7

Iqra.
Iqra.

Reputation: 763

The following code snippet brings all the occurrences' count of the list's item, hope this will help.

 from collections import Counter

_list = [['a', 'b', 'c', 'd', 'a'],['a', 'a', 'g', 'b', 'e', 'g'],['h', 'g', 't', 'y', 'u']]

words = Counter(c for clist in _list for c in clist)
print(words)

Upvotes: 4

falsetru
falsetru

Reputation: 368954

Using generator expression with set:

>>> from collections import Counter
>>> seq = [['a','b','a','c'], ['a','b','c','d']]
>>> Counter(x for xs in seq for x in set(xs))
Counter({'a': 2, 'c': 2, 'b': 2, 'd': 1})

Responding to the comment, Without generator expression:

>>> c = Counter()
>>> for xs in seq:
...     for x in set(xs):
...         c[x] += 1
...
>>> c
Counter({'a': 2, 'c': 2, 'b': 2, 'd': 1})

Upvotes: 29

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