Bootcamp week 1 problems, not related to lists. Test cases are here : https://gist.github.com/tamizhgeek/60b1a4ece4ecbb79a1e7

MiscUtils.scala

package assignments


object MiscUtils {
  def listPrimes(start : Int, end : Int) : List[Int] = {
    def collect(currentIdx : Int, newList : List[Int]) : List[Int] = {
      currentIdx match {
        case a if(a == 2 || a == 3 || (a % 2 != 0 && a % 3 != 0)) => collect(a + 1, newList :+ a)
        case a if(a >= end) => newList
        case a => collect(a + 1, newList)
      }
    }
    collect(start, List())
  }

  def sumOfMultiples(end : Int) : Int = {
    def collect(currentIdx : Int, acc : Int) : Int = {
      currentIdx match {
        case a if(a % 3 == 0 || a % 5 == 0) => collect(a + 1, acc + a)
        case a if (a >= end) => acc
        case a => collect(a + 1, acc)
      }
    }
    collect(0, 0)
  }
}

Line 8-9 - Combined to a single step

Line 14 - Yeah. My bad. Changed it now.

General Observation - Agreed. Using local variables makes more sense.