gistfile1.scala

 
case class WriteEvent(name: String, records: List[Int])

case class SingleRecord(name: String, value: Int)

val events = List( 
  WriteEvent("follow", List(1,2,3)),
  WriteEvent("block",  List(2,3,4)),
  WriteEvent("follow", List(5,6,7))
)

def convert(event: WriteEvent): List[SingleRecord] = {
  event.records.map { value =>
    SingleRecord(event.name, value)
  }
}

events.flatMap { convert(_) } 
//res9: List[SingleRecord] = List(SingleRecord(follow,1), SingleRecord(follow,2), SingleRecord(follow,3), SingleRecord(block,2), SingleRecord(block,3), SingleRecord(block,4), SingleRecord(follow,5), SingleRecord(follow,6), SingleRecord(follow,7))