aaw / levtrie

A Trie supporting fast searches based on edit distance

levtrie

This go package implements a Trie that acts like a map from strings to strings, allowing the usual Get, Set, and Delete operations on key-value associations. In addition, the Trie supports a few variations on searches for key-value pairs where the key is within a particular edit distance of a query string.

Here's an example of how you might use levtrie to find the 10 closest words to the word "sitting" that are within edit distance 2 from a list of words held in the slice wordlist:

import "github.com/aaw/levtrie"

...

t := levtrie.New()
for _, word := range wordlist {
    t.Set(word, "")
}
results := t.Suggest("sitting", 2, 10)

Or see a full example at the Go Playground.

See the godoc for this package for complete documentation.

See examples/typeahead in this repo for an extended example of implementing typeahead-style query suggestions with levtrie. You can launch a small webapp with go run examples/typeahead/typeahead.go from the top level clone of this repo that lets you type in a query box to find suggestions for spelling corrections.

All of the searches restricted by edit distance in levtrie are accomplished by generating a non-deterministic Levenshtein Automata on the fly and simulating it in parallel with the Trie search. I've described this technique in more detail in this post.