Map is used to build a new collection or set of elements by traversing a function to all elements of the collection. It can be defined formally as follows:

def map[B](f: (A) ⇒ B): Map[B]  

Let's see an example as follows:

scala> // Given a list of integers
scala> // Get a list with all the elements square.
scala> List(2, 4, 5, -6) map ( x=> x * x)
res4: List[Int] = List(4, 16, 25, 36)

While using the collection API in Scala, you often need to select the n^th elements of the list or array for example. In the next sub-section, we will explore examples of using take.