Sorted Word frequency count using python

Question

I have to count the word frequency in a text using python. I thought of keeping words in a dictionary and having a count for each of these words.

Now if I have to sort the words according to # of occurrences. Can i do it with same dictionary instead of using a new dictionary which has the key as the count and array of words as the values ?

Answer 1

WARNING: This example requires Python 2.7 or higher.

Python's built-in Counter object is exactly what you're looking for. Counting words is even the first example in the documentation:

>>> # Tally occurrences of words in a list >>> from collections import Counter >>> cnt = Counter() >>> for word in ['red', 'blue', 'red', 'green', 'blue', 'blue']: ...     cnt[word] += 1 >>> cnt Counter({'blue': 3, 'red': 2, 'green': 1}) 

As specified in the comments, Counter takes an iterable, so the above example is merely for illustration and is equivalent to:

>>> mywords = ['red', 'blue', 'red', 'green', 'blue', 'blue'] >>> cnt = Counter(mywords) >>> cnt Counter({'blue': 3, 'red': 2, 'green': 1}) 

Answer 2

You can use the same dictionary:

>>> d = { "foo": 4, "bar": 2, "quux": 3 } >>> sorted(d.items(), key=lambda item: item[1]) 

The second line prints:

[('bar', 2), ('quux', 3), ('foo', 4)] 

If you only want a sorted word list, do:

>>> [pair[0] for pair in sorted(d.items(), key=lambda item: item[1])] 

That line prints:

['bar', 'quux', 'foo']