kotlin-stdlib / kotlin / Comparator

Comparator

Common
JS
Native
1.0
interface Comparator<T>
JVM
1.1
typealias Comparator<T> = Comparator<T>

Provides a comparison function for imposing a total ordering between instances of the type T.

Functions

Common
JS
Native
1.0

compare

Compares its two arguments for order. Returns zero if the arguments are equal, a negative number if the first argument is less than the second, or a positive number if the first argument is greater than the second.

abstract fun compare(a: T, b: T): Int

Extension Functions

Common
JVM
JS
Native
1.0

reversed

Returns a comparator that imposes the reverse ordering of this comparator.

fun <T> Comparator<T>.reversed(): Comparator<T>
Common
JVM
JS
Native
1.0

then

Combines this comparator and the given comparator such that the latter is applied only when the former considered values equal.

infix fun <T> Comparator<T>.then(
    comparator: Comparator<in T>
): Comparator<T>
Common
JVM
JS
Native
1.0

thenBy

Creates a comparator comparing values after the primary comparator defined them equal. It uses the function to transform value to a Comparable instance for comparison.

fun <T> Comparator<T>.thenBy(
    selector: (T) -> Comparable<*>?
): Comparator<T>

Creates a 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.

fun <T, K> Comparator<T>.thenBy(
    comparator: Comparator<in K>,
    selector: (T) -> K
): Comparator<T>
Common
JVM
JS
Native
1.0

thenByDescending

Creates a descending comparator using the primary comparator and the function to transform value to a Comparable instance for comparison.

fun <T> Comparator<T>.thenByDescending(
    selector: (T) -> Comparable<*>?
): 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.

fun <T, K> Comparator<T>.thenByDescending(
    comparator: Comparator<in K>,
    selector: (T) -> K
): Comparator<T>
Common
JVM
JS
Native
1.0

thenComparator

Creates a comparator using the primary comparator and function to calculate a result of comparison.

fun <T> Comparator<T>.thenComparator(
    comparison: (a: T, b: T) -> Int
): Comparator<T>
Common
JVM
JS
Native
1.0

thenDescending

Combines this comparator and the given comparator such that the latter is applied only when the former considered values equal.

infix fun <T> Comparator<T>.thenDescending(
    comparator: Comparator<in T>
): Comparator<T>