Question

Simply, I have two lists and I need to extract the new elements added to one of them.
I have the following

val x = List(1,2,3)
val y = List(1,2,4)

val existing :List[Int]= x.map(xInstance => {
      if (!y.exists(yInstance =>
        yInstance == xInstance))
        xInstance
    })

Result :existing: List[AnyVal] = List((), (), 3)

I need to remove all other elements except the numbers with the minimum cost.

Answer 1

The easy way is to use filter instead so there’s nothing to remove;

val existing :List[Int] = 
  x.filter(xInstance => !y.exists(yInstance => yInstance == xInstance))