Question

Please show me how to rewrite toString in a functional way.

The code is ok, but nothing to be proud of, there are 3 temporary variables in it.

class Field(x: Int, y: Int) {
  val value = init(x,y)
  private def init(x: Int, y: Int) = List.fill(x,y)(new Cell)
  override def toString(): String = {
    val temp = new StringBuilder
    for(i <- value) {
      for(j <- i) {
        temp.append(j.toString())
      }
      temp.append("\n")
    }
    temp.mkString
  }
}

Thanks guys!

Answer 1

What about this (look ma! one line):

override def toString() = value.map(_.mkString).mkString("\n")

Sometimes it frightens me how compact Scala code can be…

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BTW if you don’t need to reuse init() method you can simply say:

val value = List.fill(x,y)(new Cell)