kotlin-stdlib/kotlin.collections/lastIndex

lastIndex

val <T> Array<out T>.lastIndex: Int(source)
val ByteArray.lastIndex: Int(source)
val ShortArray.lastIndex: Int(source)
val IntArray.lastIndex: Int(source)
val LongArray.lastIndex: Int(source)
val FloatArray.lastIndex: Int(source)
val DoubleArray.lastIndex: Int(source)
val BooleanArray.lastIndex: Int(source)
val CharArray.lastIndex: Int(source)

Returns the last valid index for the array.

Since Kotlin

1.0
@ExperimentalUnsignedTypes
val UIntArray.lastIndex: Int(source)
@ExperimentalUnsignedTypes
val ULongArray.lastIndex: Int(source)
@ExperimentalUnsignedTypes
val UByteArray.lastIndex: Int(source)
@ExperimentalUnsignedTypes
val UShortArray.lastIndex: Int(source)

Returns the last valid index for the array.

Since Kotlin

1.3
val <T> List<T>.lastIndex: Int(source)

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
}