How to split a sequence into two pieces by predicate?

Question

How do I split a sequence into two lists by a predicate?

Alternative: I can use filter and filterNot, or write my own method, but isn\'t th

Answer 1

You can also use foldLeft if you need something a little extra. I just wrote some code like this when partition didn't cut it:

val list:List[Person] = /* get your list */
val (students,teachers) = 
  list.foldLeft(List.empty[Student],List.empty[Teacher]) {
    case ((acc1, acc2), p) => p match {
      case s:Student => (s :: acc1, acc2)
      case t:Teacher  => (acc1, t :: acc2)
    }
  }