go-patricia

README

go-patricia

Documentation: GoDoc
Build Status:
Test Coverage: Comming as soon as Drone.io people update their Go.

About

A generic patricia trie (also called radix tree) implemented in Go (Golang).

The patricia trie as implemented in this library enables fast visiting of items in some particular ways:

1. visit all items saved in the tree,
2. visit all items matching particular prefix (visit subtree), or
3. given a string, visit all items matching some prefix of that string.

[]byte type is used for keys, interface{} for values.

Trie is not thread safe. Synchronize the access yourself.

State of the Project

Apparently some people are using this, so the API should not change often. Any ideas on how to make the library better are still welcome.

More (unit) testing would be cool as well...

Usage

Import the package from GitHub first.

import "github.com/tchap/go-patricia/patricia"

Then you can start having fun.

printItem := func(prefix patricia.Prefix, item patricia.Item) error {
	fmt.Printf("%q: %v\n", prefix, item)
	return nil
}

// Create a new tree.
trie := NewTrie()

// Insert some items.
trie.Insert(Prefix("Pepa Novak"), 1)
trie.Insert(Prefix("Pepa Sindelar"), 2)
trie.Insert(Prefix("Karel Macha"), 3)
trie.Insert(Prefix("Karel Hynek Macha"), 4)

// Just check if some things are present in the tree.
key := Prefix("Pepa Novak")
fmt.Printf("%q present? %v\n", key, trie.Match(key))
// "Pepa Novak" present? true
key = Prefix("Karel")
fmt.Printf("Anybody called %q here? %v\n", key, trie.MatchSubtree(key))
// Anybody called "Karel" here? true

// Walk the tree.
trie.Visit(printItem)
// "Pepa Novak": 1
// "Pepa Sindelar": 2
// "Karel Macha": 3
// "Karel Hynek Macha": 4

// Walk a subtree.
trie.VisitSubtree(Prefix("Pepa"), printItem)
// "Pepa Novak": 1
// "Pepa Sindelar": 2

// Modify an item, then fetch it from the tree.
trie.Set(Prefix("Karel Hynek Macha"), 10)
key = Prefix("Karel Hynek Macha")
fmt.Printf("%q: %v\n", key, trie.Get(key))
// "Karel Hynek Macha": 10

// Walk prefixes.
prefix := Prefix("Karel Hynek Macha je kouzelnik")
trie.VisitPrefixes(prefix, printItem)
// "Karel Hynek Macha": 10

// Delete some items.
trie.Delete(Prefix("Pepa Novak"))
trie.Delete(Prefix("Karel Macha"))

// Walk again.
trie.Visit(printItem)
// "Pepa Sindelar": 2
// "Karel Hynek Macha": 10

// Delete a subtree.
trie.DeleteSubtree(Prefix("Pepa"))

// Print what is left.
trie.Visit(printItem)
// "Karel Hynek Macha": 10

License

MIT, check the LICENSE file.