How to call a method n times in Scala?

Question

I have a case where I want to call a method n times, where n is an Int. Is there a good way to do this in a \"functional\" way in Scala?

case class Event(name: S         


        

Answer 1

A more functional solution would be to use a fold with an immutable queue and Queue's fill and drop methods:

 val queue = lst.foldLeft(Queue.empty[Option[BigDecimal]]) { (q, e) =>
   e.name match {
     case "supply" => q ++ Queue.fill(e.quantity)(e.value)
     case "sale"   => q.drop(e.quantity)
   }
 }

Or even better, capture your "supply"/"sale" distinction in subclasses of Event and avoid the awkward Option[BigDecimal] business:

sealed trait Event { def quantity: Int }
case class Supply(quantity: Int, value: BigDecimal) extends Event
case class Sale(quantity: Int) extends Event

val lst = List(
  Supply(3, BigDecimal("39.00")),
  Sale(1),
  Supply(1, BigDecimal("41.00"))
)

val queue = lst.foldLeft(Queue.empty[BigDecimal]) { (q, e) => e match {
  case Sale(quantity)          => q.drop(quantity)
  case Supply(quantity, value) => q ++ Queue.fill(quantity)(value)
}}

This doesn't directly answer your question (how to call a function a specified number of times), but it's definitely more idiomatic.