take_randoms.go

package main

import (
  "fmt"
	"math/rand"
	"time"
)

type connection struct {
	name     string
	affinity float64
}

var connections = []connection{
	{"abe", 0.3},
	{"bob", 0.2},
	{"carly", 0.4},
	{"dave", 0.7},
	{"evan", 0.1},
	{"francesca", 0.3},
	{"gary", 0.4},
	{"hogarth", 2.0},
	{"ingrid", 0.4},
	{"jorthon", 0.5},
}

func sum_affinities() float64 {
	acc := 0.0
	for _, c := range connections {
		acc += c.affinity
	}
	return acc
}

func gen_number() float64 {
	return sum_affinities() * rand.Float64()
}

func pick(n int) []string {
	inner := func() string {
		n, acc := gen_number(), 0.0
		for i, c := range connections {
			acc += c.affinity
			if acc > n {
				connections = append(connections[:i], connections[i+1:]...)
				return c.name
			}
		}
		panic("not reached")
	}
	picked := make([]string, 0, n)
	for i := 0; i < n; i++ {
		picked = append(picked, inner())
	}
	return picked
}

func main() {
	rand.Seed(time.Now().UnixNano())
	fmt.Println(pick(5))
}