Scala Collections - Map Method

map() method is a member of TraversableLike trait, it is used to run a predicate method on each elements of a collection. It returns a new collection.

Syntax

The following is the syntax of map method.

def map[B](f: (A) ? B): Traversable[B]

Here, map method takes a prediate function as a parameter. This method returns the updated collection.

Usage

Below is an example program of showing how to use map method −

Example

object Demo {
   def main(args: Array[String]) = {
      val list = List(1, 2, 3 ,4)
      //apply operation to get twice of each element.
      val result = list.map(_ * 2)
      //print result
      println(result)      
   }
}

Save the above program in Demo.scala. The following commands are used to compile and execute this program.

Command

\>scalac Demo.scala
\>scala Demo

Output

List(2, 4, 6, 8)