How to find set of most frequently occurring word-pairs in a file using python?

Question

I have a data set as follows:

"485","AlterNet","Statistics","Estimation","Narnia","Two and half men"
"717","I like Sheen", "Narnia", "Statistics", "Estimation"
"633","MachineLearning","AI","I like Cars, but I also like bikes"
"717","I like Sheen","MachineLearning", "regression", "AI"
"136","MachineLearning","AI","TopGear"

and so on

I want to find out the most frequently occurring word-pairs e.g.

(Statistics,Estimation:2)
(Statistics,Narnia:2)
(Narnia,Statistics)
(MachineLearning,AI:3)

The two words could be in any order and at any distance from each other

Can someone suggest a possible solution in python? This is a very large data set.

Any suggestion is highly appreciated

So this is what I tried after suggestions from @275365

@275365 I tried the following with input read from a file

    def collect_pairs(file):
        pair_counter = Counter()
        for line in open(file):
            unique_tokens = sorted(set(line))  
            combos = combinations(unique_tokens, 2)
            pair_counter += Counter(combos)
            print pair_counter

    file = ('myfileComb.txt')
    p=collect_pairs(file)

text file has same number of lines as the original one but has only unique tokens in a particular line. I don't know what am I doing wrong since when I run this it splits the words in letters rather than giving output as combinations of words. When I run this file it outputs split letters rather than combinations of words as expected. I dont know where I am making a mistake.

Answer 1

You might start with something like this, depending on how large your corpus is:

>>> from itertools import combinations
>>> from collections import Counter

>>> def collect_pairs(lines):
    pair_counter = Counter()
    for line in lines:
        unique_tokens = sorted(set(line))  # exclude duplicates in same line and sort to ensure one word is always before other
        combos = combinations(unique_tokens, 2)
        pair_counter += Counter(combos)
    return pair_counter

The result:

>>> t2 = [['485', 'AlterNet', 'Statistics', 'Estimation', 'Narnia', 'Two and half men'], ['717', 'I like Sheen', 'Narnia', 'Statistics', 'Estimation'], ['633', 'MachineLearning', 'AI', 'I like Cars, but I also like bikes'], ['717', 'I like Sheen', 'MachineLearning', 'regression', 'AI'], ['136', 'MachineLearning', 'AI', 'TopGear']]
>>> pairs = collect_pairs(t2)
>>> pairs.most_common(3)
[(('MachineLearning', 'AI'), 3), (('717', 'I like Sheen'), 2), (('Statistics', 'Estimation'), 2)]

Do you want numbers included in these combinations or not? Since you didn't specifically mention excluding them, I have included them here.

EDIT: Working with a file object

The function that you posted as your first attempt above is very close to working. The only thing you need to do is change each line (which is a string) into a tuple or list. Assuming your data looks exactly like the data you posted above (with quotation marks around each term and commas separating the terms), I would suggest a simple fix: you can use ast.literal_eval. (Otherwise, you might need to use a regular expression of some kind.) See below for a modified version with ast.literal_eval:

from itertools import combinations
from collections import Counter
import ast

def collect_pairs(file_name):
    pair_counter = Counter()
    for line in open(file_name):  # these lines are each simply one long string; you need a list or tuple
        unique_tokens = sorted(set(ast.literal_eval(line)))  # eval will convert each line into a tuple before converting the tuple to a set
        combos = combinations(unique_tokens, 2)
        pair_counter += Counter(combos)
    return pair_counter  # return the actual Counter object

Now you can test it like this:

file_name = 'myfileComb.txt'
p = collect_pairs(file_name)
print p.most_common(10)  # for example