lastIndex

val <T> Array<out T>.lastIndex: Int(source)

Returns the last valid index for the array.

Since Kotlin

1.0

Returns the index of the last item in the list or -1 if the list is empty.

Since Kotlin

1.0

Samples

import kotlin.test.*

fun main() { 
   //sampleStart 
   println(emptyList<Any>().lastIndex) // -1
val list = listOf("a", "x", "y")
println(list.lastIndex) // 2
println(list[list.lastIndex]) // y 
   //sampleEnd
}