Scalaでソート List#sort, Sorting.stableSort

sort.scala

// List#sort, Sorting.stableSort

import scala.collection.mutable
import scala.util.Sorting

List(1, 3, 2).sort(_ < _) // List(1, 2, 3)

val ar = Array(1, 3, 2)
Sorting.stableSort(ar)
ar                                                // Array(1, 2, 3)
Sorting.stableSort(ar, (a: Int, b: Int) => a > b)
ar                                                // Array(3, 2, 1)

val mm = mutable.Map(1 -> 70, 2 -> 50)
val sorted =                              // sorted: Array((2,50), (1,70))
  Sorting.stableSort(mm.toSeq,
    (a:(Int, Int), b:(Int, Int)) => a._2 < b._2)