SCALA

scala concatenate list

scala> val c = a ++ b
c: List[Int] = List(1, 2, 3, 4, 5, 6)

scala concatenate list

scala> val c = a ::: b
c: List[Int] = List(1, 2, 3, 4, 5, 6)

scala merge list of strings

scala> List("a","b","c").mkString 
val res1: String = abc