README.md

Trie

Overview

Yet another thread-safe Golang Trie implementation with the focus on simplicity, performance and support of concurrency. Trie is also known as Digital Tree or Prefix Tree. It can be used as a drop-in replacement for usual Go maps with string keys.

Benchmarks

Benchmarking highly depends on the used dataset, and the provided results should only be interpreted as an example. The more keys share common prefixes (e.g. as in URLs), the less memory a trie consumes, and the faster inserts are.

BenchmarkWithPrefixTrie-4      671424      3113 ns/op     561 B/op       7 allocs/op
BenchmarkWithPrefixMap-4          343   3511734 ns/op     341 B/op       2 allocs/op
BenchmarkInsertTrie-4         1033538      1038 ns/op      73 B/op       1 allocs/op
BenchmarkInsertMap-4         12719076        94 ns/op       0 B/op       0 allocs/op
BenchmarkSearchTrie-4         1269013       924 ns/op       0 B/op       0 allocs/op
BenchmarkSearchMap-4         11612143        96 ns/op       0 B/op       0 allocs/op
BenchmarkDeleteTrie-4        14271276        75 ns/op       0 B/op       0 allocs/op
BenchmarkDeleteMap-4         71850813        16 ns/op       0 B/op       0 allocs/op

BenchmarkSearchWhileInsert    1000000      3853 ns/op       1 B/op       0 allocs/op
BenchmarkSearchWhileInsert-2   332025      4529 ns/op       0 B/op       0 allocs/op
BenchmarkSearchWhileInsert-4   263719      5301 ns/op       0 B/op       0 allocs/op

BenchmarkInsertWhileSearch     966741      2104 ns/op       1 B/op       0 allocs/op
BenchmarkInsertWhileSearch-2   381709      3721 ns/op       0 B/op       0 allocs/op
BenchmarkInsertWhileSearch-4   429175      3374 ns/op       0 B/op       0 allocs/op

Usage

Download and install the package (or use Go Modules).

$ go get github.com/Pashugan/trie

package main

import (
	"fmt"

	"github.com/Pashugan/trie"
)

var CityPopulation = []struct {
	City       string
	Population int
}{
	{"Brisbane", 2462637},
	{"Bridgeport", 144900},
	{"Bristol", 463400},
	{"Auckland", 1628900},
}

func main() {
	// Create an empty trie
	cityPop := trie.NewTrie()

	// Insert keys and corresponding values
	for _, item := range CityPopulation {
		cityPop.Insert(item.City, item.Population)
	}

	testKey := "Brisbane"

	// Fetch some data
	fmt.Printf("The population of %v is %v\n", testKey, cityPop.Search(testKey))
	// Output: The population of Brisbane is 2462637

	// Delete the key
	cityPop.Delete(testKey)
	fmt.Printf("The deleted key is now %v\n", cityPop.Search(testKey))
	// Output: The deleted key is now <nil>

	// Fetch keys starting with a prefix
	fmt.Printf("But the other cities on \"Bri\" are still there: %v\n", cityPop.WithPrefix("Bri"))
	// Output: But the other cities on "Bri" are still there: map[Bridgeport:144900 Bristol:463400]

	// Count the length of the trie
	fmt.Printf("The total number of cities left is %v\n", cityPop.Len())
	// Output: The total number of cities left is 3
}