Like any great FP language, Scala has lots of built-in functions. These functions make our code more fluent and functional; now it's time to learn some of these functions:

$ scala
Welcome to Scala 2.11.8 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_77).
Type in expressions for evaluation. Or try :help.
scala> // Creates the numbers 1,2,3,4,5 and them multiply they by 2 and creates a new Vector
scala> println ((1 to 5).map(_*2))   
Vector(2, 4, 6, 8, 10)
scala> 
scala> // Creates 1,2,3 and sum them all with each orher and return the total
scala> println ( (1 to 3).reduceLeft(_+_) )
6
scala> 
scala> // Creates 1,2,3 and multiply each number by it self and return a Vector
scala> println ( (1 to 3).map( x=> x*x ) )
Vector(1, 4, 9)
scala> 
scala> // Creates numbers 1,2,3,4 ans 5 filter only Odd numbers them multiply them odds by 2 and return a Vector
scala> println ( (1 to 5) filter { _%2 == 0 } map { _*2 } )
Vector(4, 8)
scala> 
scala> // Creates a List with 1 to 5 and them print each element being multiplyed by 2
scala> List(1,2,3,4,5).foreach ( (i:Int) => println(i * 2 ) )
2
4
6
8
10
scala> 
scala> // Creates a List with 1 to 5 and then print each element being multiplied by 2
scala> List(1,2,3,4,5).foreach ( i => println(i * 2) )
2
4
6
8
10
scala> 
scala> // Drops 3 elements from the lists
scala> println( List(2,3,4,5,6).drop(3))
List(5, 6)
scala> println( List(2,3,4,5,6) drop 3 )
List(5, 6)
scala> 
scala> // Zip 2 lists into a single one: It will take 1 element of each list and create a pair List
scala> println(  List(1,2,3,4).zip( List(6,7,8) )) 
List((1,6), (2,7), (3,8))
scala> 
scala> // Take nested lists and create a single list with flat elements
scala> println( List(List(1, 2), List(3, 4)).flatten )
List(1, 2, 3, 4)
scala> 
scala> // Finds a person in a List by Age
scala> case class Person(age:Int,name:String)
defined class Person
scala> println( List(Person(31,"Diego"),Person(40,"Nilseu")).find( (p:Person) => p.age <= 33 ) )
Some(Person(31,Diego))
scala>