stopword

stopword is a module for node and the browser that allows you to strip stopwords from an input text. In natural language processing, "Stopwords" are words that are so frequent that they can safely be removed from a text without altering its meaning.

Live stopword browser demo.

Usage

Node.js

sw = require('stopword')
// sw.removeStopwords and sw.[language code] now available

Script tag method

<script src="stopword.js"></script>

<script>
// sw.removeStopwords and sw.[language code] now available
</script>

Default (English)

By default, stopword will strip an array of "meaningless" English words

sw = require('stopword')
const oldString = 'a really Interesting string with some words'.split(' ')
const newString = sw.removeStopwords(oldString)
// newString is now [ 'really', 'Interesting', 'string', 'words' ]

Other languages

You can also specify a language other than English:

sw = require('stopword')
const oldString = 'Trädgårdsägare är beredda att pröva vad som helst för att bli av med de hatade mördarsniglarna åäö'.split(' ')
// sw.sv contains swedish stopwords
const newString = sw.removeStopwords(oldString, sw.sv)
// newString is now [ 'Trädgårdsägare', 'beredda', 'pröva', 'helst', 'hatade', 'mördarsniglarna', 'åäö' ]

Custom list of stopwords

And last, but not least, it is possible to use your own, custom list of stopwords:

sw = require('stopword')
const oldString = 'you can even roll your own custom stopword list'.split(' ')
// Just add your own list/array of stopwords
const newString = sw.removeStopwords(oldString, [ 'even', 'a', 'custom', 'stopword', 'list', 'is', 'possible']
// newString is now [ 'you', 'can', 'roll', 'your', 'own']

Removing stopwords for i.e. two languages and a custom stopword list

With spread syntax you can easily combine several stopword arrays into one. Useful for situations where two langauages are used interchangeably. Or when you have certain words that are used in every document that is not in your existing stopword arrays.

sw = require('stopword')
const oldString = 'a really interesting string with some words trädgårdsägare är beredda att pröva vad som helst för att bli av med de hatade mördarsniglarna'.split(' ')
const customStopwords = ['interesting', 'really']
const newString = sw.removeStopwords(oldString, [...sw.en, ...sw.sv, ...sw.customStopwords]
// newString is now ['string', 'words', 'trädgårdsägare', 'beredda', 'pröva', 'helst', 'hatade', 'mördarsniglarna']

API

removeStopwords

Returns an Array that represents the text with the specified stopwords removed.

• text An array of words
• stopwords An array of stopwords

sw = require('stopword')
var text = sw.removeStopwords(text[, stopwords])
// text is now an array of given words minus specified stopwords

<language code>

Arrays of stopwords for the following 54 languages are supplied:

• af - Afrikaans
• ar - Arabic, Modern Standard
• hy - Armenian
• eu - Basque
• bn - Bengali
• br - Breton
• bg - Bulgarian
• ca - Catalan
• zh - Chinese Simplified
• hr - Croatian
• cs - Czech
• da - Danish
• nl - Dutch
• en - English
• eo - Esperanto
• et - Estonian
• fa - Farsi
• fi - Finnish
• fr - French
• gl - Galician
• de - German
• el - Greek
• ha - Hausa
• he - Hebrew
• hi - Hindi
• hu - Hungarian
• id - Indonesian
• ga - Irish
• it - Italian
• ja - Japanese
• ko - Korean
• la - Latin
• lv - Latvian
• lgg - Lugbara (without diacritics)
• lggo - Lugbara official (with diacritics)
• mr - Marathi
• no - Norwegian
• pl - Polish
• pt - Portuguese
• ptbr - Portuguese (Brazilian)
• pa - Punjabi Gurmukhi
• ro - Romanian
• ru - Russian
• sk - Slovak
• sl - Slovenian
• so - Somali
• st - Sotho
• es - Spanish
• sw - Swahili
• sv - Swedish
• th - Thai
• tr - Turkish
• vi - Vietnamese
• yo - Yoruba
• zu - Zulu

sw = require('stopword')
norwegianStopwords = sw.no
// norwegianStopwords now contains an Array of norwgian stopwords

Languages with no space between words

ja Japanese, th Thai and zh Chinese Simplified and some of the other languages supported have no space between words. For these languages you need to split the text into an array of words in another way than just textString.split(' '). You can check out TinySegmenter for Japanese and chinese-tokenizer for Chinese.

Your language missing?

If you can't find a stopword file for your language, you can try creating one with stopword-trainer. We're happy to help you in the process.