How do I sort a collection of Lists in lexicographic order in Scala?

Question

If A has the Ordered[A] trait, I\'d like to be able to have code that works like this

val collection: List[List[A]] = ... // constr         


        

Answer 1

Just because I already implemented this another way, here is a non-recursive version that does not use return:

new Ordering[Seq[String]]() {
  override def compare(x: Seq[String], y: Seq[String]): Int = {
    x.zip(y).foldLeft(None: Option[Int]){ case (r, (v, w)) =>
        if(r.isDefined){
          r
        } else {
          val comp = v.compareTo(w)
          if(comp == 0) None
          else Some(comp)
        }
      }.getOrElse(x.size.compareTo(y.size))
    }
  }