Filter condition using filtered value

Question

I would like to filter collection, so distance between adjacent elements would be at least 5.

So List(1, 2, 3, 4, 5, 6, 7, 11, 20) will become List(1, 6, 11, 20).

Is it possible to achieve in one pass using filter? What would be scala-way?

Answer 1

How about this one-liner:

scala> l.foldLeft(Vector(l.head)) { (acc, item) => if (item - acc.last >= 5) acc :+ item else acc }

res7: scala.collection.immutable.Vector[Int] = Vector(1, 6, 11, 20)