flatmap option

flatmapoption.scala

val o4 = Option(4)                        //> o4  : Option[Int] = Some(4)
val o5: Option[Int] = None                //> o5  : Option[Int] = None
	
val m1 = o4 map ("Num " + _ * 2)          //> m1  : Option[String] = Some(Num 8)
val m2 = o5 map ("Num " + _ * 2)          //> m2  : Option[String] = None
	
val f1 = for(i <- o4) yield "Num " + i * 3//> f1  : Option[String] = Some(Num 12)
val f2 = for(i <- o5) yield "Num " + i * 3//> f2  : Option[String] = None
	
val fm1 = o4 flatMap(i => Option("Num " + i * 4))  //> fm1  : Option[String] = Some(Num 16)
val fm2 = o5 flatMap(i => Option("Num " + i * 4))  //> fm2  : Option[String] = None

o4 foreach (println(_))                   //> 4
o5 foreach (println(_))