scala - 重複除去 ref: http://qiita.com/ryoppy@github/items/8fb6e77898a8f9258126

file0.scala

class Bench {
  @Benchmark
  def set2seq(): Unit = (1 to 100).combinations(2).toList.flatten.toSet.toSeq

  @Benchmark
  def distinct(): Unit = (1 to 100).combinations(2).toList.flatten.distinct
}

file1.txt

[info] Benchmark           Mode  Samples    Score  Score error  Units
[info] f.Bench.set2seq    thrpt        3   90.893      495.577  ops/s
[info] f.Bench.distinct   thrpt        3  109.927       75.496  ops/s

file2.scala

@State(Scope.Thread)
class Bench {
  val list: Seq[Int] = (1 to 100).combinations(2).toList.flatten

  @Benchmark
  def set2seq(): Unit = list.toSet.toSeq

  @Benchmark
  def distinct(): Unit = list.distinct
}

file3.txt

[info] Benchmark            Mode  Samples      Score  Score error  Units
[info] f.Bench.distinct    thrpt        3  13111.451     3086.943  ops/s
[info] f.Bench.set2seq     thrpt        3   5717.012     4046.475  ops/s