Getting a random subset of size (N * percentage) of a slice of size N.

incidental_complexity.go

func RandomSubset(containers []*docker.Container, percentage float64) []*docker.Container {
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	length := len(containers)
	numberOfElementsWeWant := int64(percentage * float64(length))
	randomIndices := r.Perm(length)[0:numberOfElementsWeWant]

	var selected []*docker.Container

	for _, idx := range randomIndices {
		selected = append(selected, containers[idx])
	}

	return selected
}