Scala: Filtering based on type

Question

I\'m learning Scala as it fits my needs well but I am finding it hard to structure code elegantly. I\'m in a situation where I have a List x and wa

Answer 1

If the list only contains subclasses of AnyRef, becaus of the method getClass. You can do this:

scala> case class Person(name: String)                                                           
defined class Person

scala> case class Pet(name: String)                                                              
defined class Pet

scala> val l: List[AnyRef] = List(Person("Walt"), Pet("Donald"), Person("Disney"), Pet("Mickey"))
l: List[AnyRef] = List(Person(Walt), Pet(Donald), Person(Disney), Pet(Mickey))

scala> val groupedByClass = l.groupBy(e => e.getClass)
groupedByClass: scala.collection.immutable.Map[java.lang.Class[_],List[AnyRef]] = Map((class Person,List(Person(Walt), Person(Disney))), (class Pet,List(Pet(Donald), Pet(Mickey))))

scala> groupedByClass(classOf[Pet])(0).asInstanceOf[Pet]
res19: Pet = Pet(Donald)