5.2 KiB
string-similarity
Finds degree of similarity between two strings, based on Dice's Coefficient, which is mostly better than Levenshtein distance.
Table of Contents
Usage
For Node.js
Install using:
npm install string-similarity --save
In your code:
var stringSimilarity = require('string-similarity');
var similarity = stringSimilarity.compareTwoStrings('healed', 'sealed');
var matches = stringSimilarity.findBestMatch('healed', ['edward', 'sealed', 'theatre']);
For browser apps
Include <script src="//unpkg.com/string-similarity/umd/string-similarity.min.js"></script>
to get the latest version.
Or <script src="//unpkg.com/string-similarity@4.0.1/umd/string-similarity.min.js"></script>
to get a specific version (4.0.1) in this case.
This exposes a global variable called stringSimilarity
which you can start using.
<script>
stringSimilarity.compareTwoStrings('what!', 'who?');
</script>
(The package is exposed as UMD, so you can consume it as such)
API
The package contains two methods:
compareTwoStrings(string1, string2)
Returns a fraction between 0 and 1, which indicates the degree of similarity between the two strings. 0 indicates completely different strings, 1 indicates identical strings. The comparison is case-sensitive.
Arguments
- string1 (string): The first string
- string2 (string): The second string
Order does not make a difference.
Returns
(number): A fraction from 0 to 1, both inclusive. Higher number indicates more similarity.
Examples
stringSimilarity.compareTwoStrings('healed', 'sealed');
// → 0.8
stringSimilarity.compareTwoStrings('Olive-green table for sale, in extremely good condition.',
'For sale: table in very good condition, olive green in colour.');
// → 0.6060606060606061
stringSimilarity.compareTwoStrings('Olive-green table for sale, in extremely good condition.',
'For sale: green Subaru Impreza, 210,000 miles');
// → 0.2558139534883721
stringSimilarity.compareTwoStrings('Olive-green table for sale, in extremely good condition.',
'Wanted: mountain bike with at least 21 gears.');
// → 0.1411764705882353
findBestMatch(mainString, targetStrings)
Compares mainString
against each string in targetStrings
.
Arguments
- mainString (string): The string to match each target string against.
- targetStrings (Array): Each string in this array will be matched against the main string.
Returns
(Object): An object with a ratings
property, which gives a similarity rating for each target string, a bestMatch
property, which specifies which target string was most similar to the main string, and a bestMatchIndex
property, which specifies the index of the bestMatch in the targetStrings array.
Examples
stringSimilarity.findBestMatch('Olive-green table for sale, in extremely good condition.', [
'For sale: green Subaru Impreza, 210,000 miles',
'For sale: table in very good condition, olive green in colour.',
'Wanted: mountain bike with at least 21 gears.'
]);
// →
{ ratings:
[ { target: 'For sale: green Subaru Impreza, 210,000 miles',
rating: 0.2558139534883721 },
{ target: 'For sale: table in very good condition, olive green in colour.',
rating: 0.6060606060606061 },
{ target: 'Wanted: mountain bike with at least 21 gears.',
rating: 0.1411764705882353 } ],
bestMatch:
{ target: 'For sale: table in very good condition, olive green in colour.',
rating: 0.6060606060606061 },
bestMatchIndex: 1
}
Release Notes
2.0.0
- Removed production dependencies
- Updated to ES6 (this breaks backward-compatibility for pre-ES6 apps)
3.0.0
- Performance improvement for
compareTwoStrings(..)
: now O(n) instead of O(n^2) - The algorithm has been tweaked slightly to disregard spaces and word boundaries. This will change the rating values slightly but not enough to make a significant difference
- Adding a
bestMatchIndex
to the results forfindBestMatch(..)
to point to the best match in the suppliedtargetStrings
array
3.0.1
- Refactoring: removed unused functions; used
substring
instead ofsubstr
- Updated dependencies
4.0.1
- Distributing as an UMD build to be used in browsers.