scalafunctionfor-loopuser-defined-functionsflow-control

Checking for evens on a list, and getting a type mismatch in Scala

I'm trying to check the contents of a list to see if an element is even or not. Here is the code:

def listEvenChecker2(aList: List[Int]): Boolean = 
{
    for (elem <- aList)
    {
        if (elem % 2 == 0)
        {
           return true
        }
        else 
        {
            return false
        }
    }
}

val myList = List(1,2,3,4,5,6,7)
println(listEvenChecker2(myList))

Why am I getting this error:

enter image description here

Solution

  • If you what to check whether there is at least one even value, use exists:

    def listEvenChecker2(aList: List[Int]): Boolean = 
  aList.exists(_%2 == 0)

    If you want to check that they are all even, use forall:

    def listEvenChecker2(aList: List[Int]): Boolean = 
  aList.forall(_%2 == 0)