Go Weighted Random

A Go library for efficient weighted random selection using Vose's Alias Method.

Performance

Dimension	Complexity
Time	O(1)
Memory	O(n)

Installation

$ go get github.com/nikole-dunixi/go-weighted-random

Example Usage

You will need to initialize an instance of rand.Random, or any other implementation that satisfies the local interface RandIntN, and any items that need to be selected.

There is no imposed limitations around concurrency, except for those needed to support the standard library rand.Random.

rand := rand.New(rand.NewSource(time.Now().Unix()))
wr := weightedrand.NewAliasVoseMethod(rand,
  weightedrand.WeightedItem[string, int]{
    Item:   "Hollow Knight: Silksong",
    Weight: 1,
  },
  weightedrand.WeightedItem[string, int]{
    Item:   "Don't Starve Together",
    Weight: 3,
  },
  weightedrand.WeightedItem[string, int]{
    Item:   "Stardew Valley",
    Weight: 3,
  },
  weightedrand.WeightedItem[string, int]{
    Item:   "Deep Rock Galactic",
    Weight: 7,
  },
)

for range 5 {
  fmt.Printf("%s\n", wr.Next())
}