quick comparison in processing collections in Ruby vs Scala

Benchmark.scala

import scala.util.Random
import scala.collection.mutable.ArrayBuffer
import scala.annotation.tailrec
import scala.collection.immutable.Vector

object Benchmark {

  @tailrec def repeat(n: Int)(f: => Unit) {
    if (n > 0) { f; repeat(n - 1)(f) }
  }

  def main(args: Array[String]) {
    val start = System.currentTimeMillis
    repeat(100) {
      val letterList = new ArrayBuffer[Char]()
      val alphabet = ('a' until 'z').toArray
      repeat(100000) {  letterList.append( alphabet(Random.nextInt(25)) ) }
      val distinct = letterList.distinct
      val pick = distinct(Random.nextInt(distinct.size))
      val (before, after) = letterList.partition { _ > pick }
    }
    println(System.currentTimeMillis - start)
  }

}

collection.rb

start = Time.now
100.times do
  letter_list = []
  alphabet = ('a'..'z').to_a
  100_000.times{ letter_list << alphabet[rand(26)] }
  pick = letter_list.uniq[rand(26)]
  before, after = letter_list.partition{|n| n > pick}
end
p (Time.now - start) * 1000

collection.scala

import scala.util.Random

val start = System.currentTimeMillis
(1 to 100).foreach { _ =>
  val alphabet = ('a' to 'z').toArray
  val letterList = (0 to 100000).map( _ => alphabet(Random.nextInt(26)) )
  val pick = letterList.distinct(Random.nextInt(26))
  val (before, after) = letterList.partition{ _ > pick }
}
println(System.currentTimeMillis - start)