Add keys conditionally in Scala to a Map[String,String]?-CodePudding

I want to add keys as shown below:

val x = false
  val y = Map[String,String](
    "name" -> "AB",
    if(x) "placement"->"pc" else null
  )
  println(y)

Note that its an immutable map, this works when x is true but throws runtime error when x is false, I tried to put else Unit but that doesn't work as well.

Can someone point me the most elegant as well as optimized syntax to do so?

CodePudding user response：

Sorted it like this:

val x = true
  val y = Map[String,String](
    "name" -> "AB"
  )    (if(x) Map[String,String]("place"->"pc") else Nil)

still wondering if this is good or something better should be used.

CodePudding user response：

One more option is

val y = Map[String, String](
  Seq("name" -> "AB")   
    (if (x) Seq("placement" -> "pc") else Seq()): _*
)

val y = (Seq("name" -> "AB")   
  (if (x) Seq("placement" -> "pc") else Seq())).toMap

val y = (Seq("name" -> "AB")   
  Option.when(x)("placement" -> "pc").toSeq).toMap

This is not shorter but maybe a little less confusing than if (...) Map(...) else List(...).