How to count occurrence of word in a list using a dictionary

Question

I have a list of words

words = ['two', 'forks.', 'one', 'knife.', 'two', 'glasses.','one', 
'plate.', 'one', 'naptkin.', 'his,' 'glasses.', 'his', 'knife.']

and need to count the occcurence of words using a dictionary like so.

word_counts = {'two':2, 'one':3, 'forks.':1, 'knife.':2, \
           'glasses.':2, 'plate.':1, 'naptkin.':1, 'his':2}

How would I go about doing this? Thanks for the help!

score 4 · Answer 1 · answered Jul 28 '19 at 00:20

4

from collections import Counter
words = ['two', 'forks.', 'one', 'knife.', 'two', 'glasses.','one', 'plate.', 'one', 'naptkin.', 'his,' 'glasses.', 'his', 'knife.']
dict(Counter(words))

answered Jul 28 '19 at 00:20

ComplicatedPhenomenon

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Didn't know about counter - good one. – logicOnAbstractions Jul 28 '19 at 00:21
Little complex for what I've learned so far, but I'll keep this in mind for future use! – Leonardo Echeverria Jul 28 '19 at 00:23
@Leonardo `Counter`s are dictionaries specialized for counting. You can just use them like regular dictionaries if all you need is to retrieve the word counts. – GZ0 Jul 28 '19 at 00:45
@LeonardoEcheverria it's an import and 1 line of code, far less complex than looping and manipulating dictionaries – Iain Shelvington Jul 28 '19 at 01:00
`Counter` is a subclass of `dict`, no need to convert. – RoadRunner Jul 28 '19 at 01:09
1

@RoadRunner It's for the sake of output format – ComplicatedPhenomenon Jul 28 '19 at 01:10

score 0 · Accepted Answer · answered Jul 28 '19 at 00:20

0

words = ['two', 'forks.', 'one', 'knife.', 'two', 'glasses.','one',
'plate.', 'one', 'naptkin.', 'his,' 'glasses.', 'his', 'knife.']

d = {}
for w in words:
    if w in d.keys():
        d[w] += 1
    else:
        d[w] = 1

print(d)

answered Jul 28 '19 at 00:20

logicOnAbstractions

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score 0 · Answer 3 · answered Jul 28 '19 at 00:53

The first solution is similar to that of Francky_V, but make use of the .setdefault() method. For example:

>>> d = {}
>>> d.setdefault('two', 0) # 'two' is not in d, we can set it 
0
>>> d.setdefault('two', 1000)  # 'two' is now in d, we cannot set it, returns current value
0

So, the solution:

d = {}
for word in words:
    d.setdefault(word, 0)
    d[word] += 1

The second solution makes use of collections.defaultdict:

import collections
d = collections.defaultdict(int)
for word in words:
    d[word] += 1

This works because d is a defaultdict with int for values. The first time we mention d[word], the value is automatically set to 0.

Of course, the collections.Counter is the best solution because that class is built for this purpose.

How to count occurrence of word in a list using a dictionary

3 Answers3