Function1 examples

function1.scala

// Simple way to create a Function1
val succ = (x: Int) => x + 1              //> succ  : Int => Int = <function1>
	
// Same in full version
val anonfun1 = new Function1[Int, Int] {
  // Only need to specify the apply method
  def apply(x: Int): Int = x + 1
}                                         //> anonfun1  : Int => Int = <function1>
	
// Create one more function to compose
val toStr = (x: Int) => "Num " + x        //> toStr  : Int => String = <function1>

// So we can assign and pass funtions as arguments
val a = succ                              //> a  : Int => Int = <function1>
	
List(1,2,3,4) map a                       //> res0: List[Int] = List(2, 3, 4, 5)

// Compose succ and toStr in this order
val t = succ andThen toStr                //> t  : Int => String = <function1>
	
// Check it
t(1)                                      //> res1: String = Num 2
	
// Compose reverses the order of the operants, same as mathematical composition f(g(x)) 
val t2 = toStr compose succ               //> t2  : Int => String = <function1>
	 
// Should be the same as before
t2(1)                                     //> res2: String = Num 2
	
// We can also use our "composite" function same as a regular function
List(1,2,3,4,5) map t2                    //> res3: List[String] = List(Num 2, Num 3, Num 4, Num 5, Num 6)