temperatureAvg1.scala

import scala.math.abs
// 気温リスト1~12月
val temperatureSeq:Seq[Int] =
  Seq(4, 5, 11, 17, 19, 22, 28, 28, 22, 19, 14, 7)
def diffTemperature1(tSeq: Seq[Int]) = {
  @scala.annotation.tailrec
  def f(diffSeq:Seq[Int], tSeq: Seq[Int]): Seq[Int] = {
    tSeq match {
      case head +: second +: tail =>
        f(diffSeq :+ abs(head - second), second +: tail)
      case _ =>
        diffSeq
    }
  }
  f(Seq.empty, temperatureSeq)
}
diffTemperature1(temperatureSeq)
// -> res0: Seq[Int] = List(1, 6, 6, 2, 3, 6, 0, 6, 3, 5, 7)