for Expression : Filter, Nested For Loop, Midstream variable binding...

scala> //For loop with filter

scala> val subList =  List(
     |                   ("math", 80),
     |                   ("history", 70),
     |                   ("science", 65)
     |                )
subList: List[(String, Int)] = List((math,80), (history,70), (science,65))

scala> //Syntax : for(Generator Filters)

scala> for(
     |    info <- subList
     |    //First Filter
     |    if info._1 != "math"
     |    //Second Filter
     |    if info._2 != 65
     | ){
     |    println("info -> " + info)
     | }
info -> (history,70)

scala>
     |
     | //Nested for loop with Filter

scala> //val subList:List[(String, List[Int])] =  List(

scala> val subList =  List(
     |                   ("math", List(50, 51, 52)),
     |                   ("science", List(60, 61, 62)),
     |                   ("history", List(80, 90, 100))
     |                )
subList: List[(String, List[Int])] = List((math,List(50, 51, 52)), (science,List(60, 61, 62)), (history,List(80, 90, 100)))

scala> for (
     |    info <- subList
     |    //Need semicolon to indicate each nested loop
     |    //If Braces is used instead of Paranthesis,
     |    //semicolon can be avoided
     |    if info._1 != "math";
     |    mark <- info._2
     |    if mark != 61
     | ){
     |    println("subject -> " + info._1 + ", mark -> " + mark)
     | }
subject -> science, mark -> 60
subject -> science, mark -> 62
subject -> history, mark -> 80
subject -> history, mark -> 90
subject -> history, mark -> 100

scala>
     |
     | //Nested for loop with mid stream variable binding

scala> //val subList:List[(String, List[Int])] =  List(

scala> val subList =  List(
     |                   ("math", List(50, 51, 52)),
     |                   ("science", List(60, 61, 62)),
     |                   ("history", List(80, 90, 100))
     |                )
subList: List[(String, List[Int])] = List((math,List(50, 51, 52)), (science,List(60, 61, 62)), (history,List(80, 90, 100)))

scala> for {
     |    info <- subList
     |    //Midstream variable binding
     |    //Much easier to refer 'subject' in println
     |    //statement rather than using info._1
     |    subject = info._1
     |    //Note : Semicolon is no more needed
     |    //       as we are using Braces for the
     |    //       'for' expression
     |    if subject != "math"
     |    mark <- info._2
     |    if mark != 61
     | }{
     |    println("subject -> " + subject + ", mark -> " + mark)
     | }
subject -> science, mark -> 60
subject -> science, mark -> 62
subject -> history, mark -> 80
subject -> history, mark -> 90
subject -> history, mark -> 100