Showing posts with label Set. Show all posts
Showing posts with label Set. Show all posts

Monday, June 1, 2009

Count the number of words using Python

This article represents a way to count the number of words, the number of unique words, and the number of each word occurrences in a text file.
  1. Read the text file.
    text = open("filename.txt").read()
  2. Replace non-alphanumeric characters as a whitespace.
    import re text = re.sub('[^w&^d]', ' ', text)
  3. Change all characters to lowercase.
    text = text.lower()
  4. Split words into a list.
    text = text.split()
  5. Display the number for words in the text file.
  6. Display the number of unique words in the text file.
  7. Display the number of occurrences for each word.
    from collections import defaultdict
    wordsCount = defaultdict(int)
    for word in text:
        wordsCount[word] += 1
        for word, num in wordsCount.items():
            print(word, num)

Saturday, May 16, 2009

The intersection of two Python lists using Set

Set is unordered unique collection of objects.

We can use Set to find the intersection of two lists/tuples.

Suppose that we have two lists.
>>> x = [1, 2, 3, 4, 5]
>>> y = [2, 6, 7, 3]

To find the intersection of the two lists, first change both x and y to the Set type, then use the intersection method (&).
>>> set(x) & set(y)
{2, 3}

If we need the output in list type, apply the list command, to the output.
>>> list(set(x) & set(y))
[2, 3]