In Scala how do I remove duplicates from a list?

Question

Suppose I have

val dirty = List(\"a\", \"b\", \"a\", \"c\")

Is there a list operation that returns \"a\", \"b\", \"c\"

Answer 1

You can also use recursion and pattern matching:

def removeDuplicates[T](xs: List[T]): List[T] = xs match {
  case Nil => xs
  case head :: tail => head :: removeDuplicates(for (x <- tail if x != head) yield x)
}