50x Speedup of contractions library (based on regex) using TextSearch

Embracing C wrappers

Contractions is a library that normalized language like "he's" to "he is", and "I'm" to "I am".

It was basically a bunch of regex. The slowdown becomes unbearable once you use multiple regexes; since it will be making multiple passes over the same text.

It’s great to use libraries which solve exactly the problem you are facing.

In the case of contractions, I was able to simplify the code of my library from 120 lines to 90 by relying on TextSearch. Even more, it became possible to write an additional method that wasn’t possible before with no effort.

Most impressively, it allowed a speed up of 50x.


This is loading some example data (easily available when you use scikit-learn):

from sklearn.datasets import fetch_20newsgroups

categories = ["alt.atheism", "talk.religion.misc", "comp.graphics", "sci.space"]

newsgroups = fetch_20newsgroups(
    subset="train", remove=("headers", "footers", "quotes"), categories=categories

Using contractions==0.0.18, the timing is:

from contractions import fix
for line in newsgroups.data:
# Wall time: 5.04s

exactly the same code, but using contractions>0.0.18 doing it 50 times in the same time:

from contractions import fix

for _ in range(50):
    for line in newsgroups.data:
# Wall time: 5.01s

I promise… no caching ¯\(ツ)