main.go

package main

import (
	"fmt"
	"github.com/fighterlyt/permutation"
	"reflect"
)

type Phone struct {
	ID     int
	Vendor string
}

func main() {
	phone := []Phone{
		Phone{1, "Samsung"},
		Phone{2, "HTC"},
		Phone{3, "LG"},
		Phone{4, "Sony"},
	}

	perm, _ := permutation.NewPerm(phone, func(i, j interface{}) bool {
		return reflect.ValueOf(i).FieldByName("ID").Int() < reflect.ValueOf(j).FieldByName("ID").Int()
	})

	for elem, err := perm.Next(); err == nil; elem, err = perm.Next() {
		fmt.Println(elem, perm.Left())
	}
}