filterを命令型と関数型で比較

gistfile1.scala

import collection.mutable.ListBuffer

// 命令型で書いた場合
val filtered = new ListBuffer[Int]
val numbers = List(1,2,3,4,5)
for(n <- numbers){
  if (n % 2 == 0){
    filtered += n
  }
}
println(filtered.toList)

// 関数型で書いた場合
val numbers2 = List(1,2,3,4,5)
val filtered2 = numbers2.filter(_ % 2 == 0)
println(filtered2)