inline fun <T> Comparator<T>.thenByDescending( crossinline selector: (T) -> Comparable<*>? ): Comparator<T>
Creates a descending comparator using the primary comparator and the function to transform value to a Comparable instance for comparison.
import kotlin.test.*
fun main(args: Array<String>) {
//sampleStart
val list = listOf("aa", "b", "bb", "a")
val lengthComparator = compareBy<String> { it.length }
println(list.sortedWith(lengthComparator)) // [b, a, aa, bb]
val lengthThenStringDesc = lengthComparator.thenByDescending { it }
println(list.sortedWith(lengthThenStringDesc)) // [b, a, bb, aa]
//sampleEnd
}inline fun <T, K> Comparator<T>.thenByDescending( comparator: Comparator<in K>, crossinline selector: (T) -> K ): Comparator<T>
Creates a descending comparator comparing values after the primary comparator defined them equal. It uses the selector function to transform values and then compares them with the given comparator.
import kotlin.test.*
fun main(args: Array<String>) {
//sampleStart
val list = listOf("A", "aa", "b", "bb", "a")
val lengthComparator = compareBy<String> { it.length }
println(list.sortedWith(lengthComparator)) // [A, b, a, aa, bb]
val lengthThenCaseInsensitive = lengthComparator
.thenByDescending(String.CASE_INSENSITIVE_ORDER) { it }
println(list.sortedWith(lengthThenCaseInsensitive)) // [b, A, a, bb, aa]
//sampleEnd
}
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Licensed under the Apache License, Version 2.0.
https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.comparisons/then-by-descending.html