Finding the index of an element in a list scala

Question

How do I find the index of an element in a Scala list.

val ls = List(\"Mary\", \"had\", \"a\", \"little\", \"lamb\")

I need to get 3 if I ask f

Answer 1

If you want list of all indices containing "a", then:

val ls = List("Mary", "had", "a", "little", "lamb","a")
scala> ls.zipWithIndex.filter(_._1 == "a").map(_._2)
res13: List[Int] = List(2, 5)