Scala map method on option

Question

I am new to scala, please help me with the below question.

Can we call map method on an Option? (eg Option[Int].map()?) .

If yes then could you help me with an example?

Answer 1

Here's a simple example:

val x = Option(5)

val y = x.map(_ + 10)

println(y)

This will result in Some(15) . If x were None instead, y would also be None .

Answer 2

Yes:

  val someInt = Some (2)
  val noneInt:Option[Int] = None
  val someIntRes = someInt.map (_ * 2) //Some (4)
  val noneIntRes = noneInt.map (_ * 2) //None

See docs

You can view an option as a collection that contains exactly 0 or 1 items. Mapp over the collection gives you a container with the same number of items, with the result of applying the mapping function to every item in the original.

Answer 3

Sometimes it's more convenient to use fold instead of mapping Option s. Consider the example:

scala> def printSome(some: Option[String]) = some.fold(println("Nothing provided"))(println)
printSome: (some: Option[String])Unit

scala> printSome(Some("Hi there!"))
Hi there!

scala> printSome(None)
Nothing provided

You can easily proceed with the real value inside fold , eg map it or do whatever you want, and you're safe with the default fold option which is triggered on Option#isEmpty .