Insertion-ordered ListSet

Question

ListSet (collection.immutable.ListSet) is a inverse ordered set. I need ordered set. This is a example of original ListSet:

var a = ListSet(1,2,3)
var ite =          


        

Answer 1

If you want to retrieve your elements in the order they were inserted, you need a first-in-first-out collection, so simply use a Queue.

import collection.mutable.Queue

val queue = Queue(1,2,3)
queue += 5
queue += 4

for(i <- queue)
  println(i)

prints

 1
 2
 3
 5
 4