Turning Map("a" -> 2, "b" -> 1) into seq("a","a","b") using map

Question

I am trying to turn a Map("a" -> 2, "b" -> 1) into seq("a","a","b") through the map function, Currently I am trying to run the code below giving me the desired result.

Is there a smarter way to do this? Possibly a better way through the map function?

    var multiset : Seq[T] = Seq[T]()
    var variables : Seq[T] = data.map(x => x._1).toSeq
    var variableCounts : Seq[Int] = data.map(x => x._2).toSeq
    for(x <- 0 until variables.length){
        for(y <- 0 until variableCounts(x))
            multiset = multiset :+ variables(x)
    }

Answer 1

you can do something like this: Use fill method of GenTraversableFactory def fill[A](n: Int)(elem: => A): CC[A] from the definition of fill we can see that it takes an integer and an element. Integer tell how many times we need to fill the given element.

object Demo extends App {

  val x = Map("a" -> 2, "b" -> 1)

  val p: Seq[String] = x.flatMap { tuple =>
    List.fill(tuple._2)(tuple._1)
  }.toSeq

  print(p)
//output: List(a, a, b)
}

I Hope it helps!!!

If you want to avoid tuple._1 and tuple._1 you can use the following approach.

object Demo extends App {

  val x = Map("a" -> 2, "b" -> 1)

  val p: Seq[String] = x.flatMap { case (key, value) =>
    List.fill(value)(key)
  }.toSeq

  print(p)
//output: List(a, a, b)
}