Convert Scala Array[Object] to Map

Question

I have an array with objects (Array[Organisation]). The Organisation object contains a long orgId and a string orgName.

Is there a convenient way of converting this into a Map[Long, String] (orgId, orgName)

case class OrgRegistryConfig() {

  var organisations: Array[Organisation] = _

  def toMap() : Map[Long, String] = // How??
  // Output: Map( orgId as Long -> orgName as String )

}

object OrgRegistryConfig {
  case class Organisation() {
    var orgId: Long = _
    var orgName: String = _
  }
}

Dima · Accepted Answer · 2019-03-04 13:01:31Z

5

organisations.map { o => o.orgId -> o.orgName }.toMap

^^ that should do it.

On a related note, don't use var unless you know for sure the exact reason why you must be using it (95% of cases in scala you don't need it, and it's best to just pretend that keyword does not exist, until you have enough of a grasp of the language to distinguish those rare cases when you do), and definitely not in case classes.

Also, don't declare case class members outside of the constructor. And do not create case classes without parameters.

case class OrgRegistryConfig(organizations: Array[Organization]) {
  def toMap = organizations.map { o => o.orgId -> o.orgName }.toMap
}

answered Mar 4, 2019 at 13:01

Dima

40.6k6 gold badges54 silver badges80 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Mr.Turtle Over a year ago

Hi, thank you! I am using Spring Boot ConfigurationProperties, therefor I had to replicate some Java-behavior to make it work. stackoverflow.com/a/54982686/2291510

Dima Over a year ago

Yeah ... don't use that.

Mr.Turtle Over a year ago

I can't do it differently as I know. This is a large application written in Scala & Spring Boot. The list needs to be updated in a running cloud solution without re-deploying the application. I can't put this in a database. Having it in a configmap does the work :)

Tim · Accepted Answer · 2019-03-04 13:41:00Z

2

This is probably the most efficient solution:

def toMap: Map[Long, String] =
  organisations.map(o => o.orgId -> o.orgName)(collection.breakOut)

Using breakOut means that the Map will be created directly from the Array. If you use toMap then it will create an intermediate array which is then converted to a Map.

answered Mar 4, 2019 at 13:41

Tim

27.6k2 gold badges18 silver badges32 bronze badges

Collectives™ on Stack Overflow

Convert Scala Array[Object] to Map

2 Answers 2

3 Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related