18 releases

0.11.0 Oct 26, 2023
0.10.1 Sep 8, 2022
0.10.0 Aug 15, 2022
0.9.0 Feb 28, 2022
0.3.1 Dec 16, 2020

#185 in Text processing

Download history 9/week @ 2024-01-05 5/week @ 2024-01-12 16/week @ 2024-02-09 31/week @ 2024-02-16 33/week @ 2024-02-23 37/week @ 2024-03-01 31/week @ 2024-03-08 32/week @ 2024-03-15 61/week @ 2024-03-29 19/week @ 2024-04-05

80 downloads per month


399 lines

Cover logo

Instant Segment: fast English word segmentation in Rust

Documentation Crates.io PyPI Build status License: Apache 2.0

Instant Segment is a fast Apache-2.0 library for English word segmentation. It is based on the Python wordsegment project written by Grant Jenks, which is in turn based on code from Peter Norvig's chapter Natural Language Corpus Data from the book Beautiful Data (Segaran and Hammerbacher, 2009).

For the microbenchmark included in this repository, Instant Segment is ~100x faster than the Python implementation. The API was carefully constructed so that multiple segmentations can share the underlying state to allow parallel usage.

How it works

Instant Segment works by segmenting a string into words by selecting the splits with the highest probability given a corpus of words and their occurrences.

For instance, provided that choose and spain occur more frequently than chooses and pain, and that the pair choose spain occurs more frequently than chooses pain, Instant Segment can help identify the domain choosespain.com as ChooseSpain.com which more likely matches user intent.

Read about how we built and improved Instant Segment for use in production at Instant Domain Search to help our users find relevant domains they can register.

Using the library

Python (>= 3.9)

pip install instant-segment


instant-segment = "0.8.1"


The following examples expect unigrams and bigrams to exist. See the examples (Rust, Python) to see how to construct these objects.

import instant_segment

segmenter = instant_segment.Segmenter(unigrams, bigrams)
search = instant_segment.Search()
segmenter.segment("instantdomainsearch", search)
print([word for word in search])

--> ['instant', 'domain', 'search']
use instant_segment::{Search, Segmenter};
use std::collections::HashMap;

let segmenter = Segmenter::new(unigrams, bigrams);
let mut search = Search::default();
let words = segmenter
    .segment("instantdomainsearch", &mut search)
println!("{:?}", words.collect::<Vec<&str>>())

--> ["instant", "domain", "search"]

Check out the tests for more thorough examples: Rust, Python


To run the tests run the following:

cargo t -p instant-segment --all-features

You can also test the Python bindings with:

make test-python