fun <T : Any> nullsFirst( comparator: Comparator<in T> ): Comparator<T?>
Platform and version requirements: JVM
fun <T : Any> nullsFirst( comparator: Comparator<in T> ): Comparator<T?>
Platform and version requirements: JS
Extends the given comparator of non-nullable values to a comparator of nullable values considering null value less than any other value.
import kotlin.test.*
fun main(args: Array<String>) {
//sampleStart
val list = listOf(4, null, 1, -2, 3)
val nullsFirstList = list.sortedWith(nullsFirst(reverseOrder()))
println(nullsFirstList) // [null, 4, 3, 1, -2]
val nullsLastList = list.sortedWith(nullsLast(reverseOrder()))
println(nullsLastList) // [4, 3, 1, -2, null]
//sampleEnd
}inline fun <T : Comparable<T>> nullsFirst(): Comparator<T?>
Provides a comparator of nullable Comparable values considering null value less than any other value.
import kotlin.test.*
fun main(args: Array<String>) {
//sampleStart
val list = listOf(4, null, -1, 1)
val nullsFirstList = list.sortedWith(nullsFirst())
println(nullsFirstList) // [null, -1, 1, 4]
val nullsLastList = list.sortedWith(nullsLast())
println(nullsLastList) // [-1, 1, 4, null]
//sampleEnd
}
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Licensed under the Apache License, Version 2.0.
https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.comparisons/nulls-first.html