Question

The following code can be compiled

  def isEven(a:Int)=
    if (a%2==0) true else false

  def main(args: Array[String]) {
        List(1, 10) filter isEven foreach println

but if I change to following ( List(1,10) –> List(1 to 10))

def isEven(a:Int)=
    if (a%2==0) true else false

  def main(args: Array[String]) {
        List(1 to 10) filter isEven foreach println
   }

What’s difference between List(1,10) and List(1 to 10) ?

Answer 1

List(1, 2) is simply a list with two Int elements: 1 and 2. The expression 1 to 10 creates a Range instance, so List(1 to 10) is a list with one element: a Range.