Scala case class update value

scala option case-class
bashan picture bashan · Jun 8, 2014 · Viewed 27.3k times · Source

I have a case class with 2 String members. I would like to update The second member later, so first I create an instance with String and None and later I load the data to the class and would like to update the second member with some value.

How can I do it?

Answer

Jesper picture Jesper · Jun 8, 2014

Define the case class so that the second member is a var:

case class Stuff(name: String, var value: Option[String])

Now you can create an instance of Stuff and modify the second value:

val s = Stuff("bashan", None)

s.value = Some("hello")

However, making case classes mutable is probably not a good idea. You should prefer working with immutable data structures. Instead of creating a mutable case class, make it immutable, and use the copy method to create a new instance with modified values. For example:

// Immutable Stuff
case class Stuff(name: String, value: Option[String])

val s1 = Stuff("bashan", None)

val s2 = s1.copy(value = Some("hello"))
// s2 is now: Stuff("bashan", Some("hello"))

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