CODEWITHSUNDEEP
pythonstringlistwords
Maciej Ziarko
Maciej Ziarko

Reputation: 12084

Finding the most popular words in a list

I have a list of words:

words = ['all', 'awesome', 'all', 'yeah', 'bye', 'all', 'yeah']

And I want to get a list of tuples:

[(3, 'all'), (2, 'yeah'), (1, 'bye'), (1, 'awesome')]

where each tuple is...

(number_of_occurrences, word)

The list should be sorted by the number of occurrences.

What I've done so far:

def popularWords(words):
    dic = {}
    for word in words:
        dic.setdefault(word, 0)
        dic[word] += 1
    wordsList = [(dic.get(w), w) for w in dic]
    wordsList.sort(reverse = True)
    return wordsList

The question is...

Is it Pythonic, elegant and efficient? Are you able to do it better? Thanks in advance.

Upvotes: 13

Views: 19894

Answers (3)

SiggyF
SiggyF

Reputation: 23145

You can use the counter for this.

import collections
words = ['all', 'awesome', 'all', 'yeah', 'bye', 'all', 'yeah']
counter = collections.Counter(words)
print(counter.most_common())
>>> [('all', 3), ('yeah', 2), ('bye', 1), ('awesome', 1)]

It gives the tuple with reversed columns.

From the comments: collections.counter is >=2.7,3.1. You can use the counter recipe for lower versions.

Upvotes: 16

Kenan Banks
Kenan Banks

Reputation: 211922

The defaultdict collection is what you are looking for:

from collections import defaultdict

D = defaultdict(int)
for word in words:
    D[word] += 1

That gives you a dict where keys are words and values are frequencies. To get to your (frequency, word) tuples:

tuples = [(freq, word) for word,freq in D.iteritems()]

If using Python 2.7+/3.1+, you can do the first step with a builtin Counter class:

from collections import Counter
D = Counter(words)

Upvotes: 6

Jason S
Jason S

Reputation: 189626

Is it Pythonic, elegant and efficient?

Looks good to me...

Are you able to do it better?

"better"? If it's understandable, and efficient, isn't that enough?

Maybe look at defaultdict to use that instead of setdefault.

Upvotes: 2

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