kotlin-stdlib/kotlin.comparisons

Package-level declarations

Helper functions for creating Comparator instances.

Functions

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fun <T> compareBy(vararg selectors: (T) -> Comparable<*>?): Comparator<T>

Creates a comparator using the sequence of functions to calculate a result of comparison. The functions are called sequentially, receive the given values a and b and return Comparable objects. As soon as the Comparable instances returned by a function for a and b values do not compare as equal, the result of that comparison is returned from the Comparator.

Since Kotlin 1.0
inline fun <T> compareBy(crossinline selector: (T) -> Comparable<*>?): Comparator<T>

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

Since Kotlin 1.0
inline fun <T, K> compareBy(comparator: Comparator<in K>, crossinline selector: (T) -> K): Comparator<T>

Creates a comparator using the selector function to transform values being compared and then applying the specified comparator to compare transformed values.

Since Kotlin 1.0
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inline fun <T> compareByDescending(crossinline selector: (T) -> Comparable<*>?): Comparator<T>

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

Since Kotlin 1.0
inline fun <T, K> compareByDescending(comparator: Comparator<in K>, crossinline selector: (T) -> K): Comparator<T>

Creates a descending comparator using the selector function to transform values being compared and then applying the specified comparator to compare transformed values.

Since Kotlin 1.0
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fun <T : Comparable<*>> compareValues(a: T?, b: T?): Int

Compares two nullable Comparable values. Null is considered less than any value.

Since Kotlin 1.0
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fun <T> compareValuesBy(a: T, b: T, vararg selectors: (T) -> Comparable<*>?): Int

Compares two values using the specified functions selectors to calculate the result of the comparison. The functions are called sequentially, receive the given values a and b and return Comparable objects. As soon as the Comparable instances returned by a function for a and b values do not compare as equal, the result of that comparison is returned.

Since Kotlin 1.0
inline fun <T> compareValuesBy(a: T, b: T, selector: (T) -> Comparable<*>?): Int

Compares two values using the specified selector function to calculate the result of the comparison. The function is applied to the given values a and b and return Comparable objects. The result of comparison of these Comparable instances is returned.

Since Kotlin 1.0
inline fun <T, K> compareValuesBy(a: T, b: T, comparator: Comparator<in K>, selector: (T) -> K): Int

Compares two values using the specified selector function to calculate the result of the comparison. The function is applied to the given values a and b and return objects of type K which are then being compared with the given comparator.

Since Kotlin 1.0
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fun <T : Comparable<T>> naturalOrder(): Comparator<T>

Returns a comparator that compares Comparable objects in natural order.

Since Kotlin 1.0
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inline fun <T : Comparable<T>> nullsFirst(): Comparator<T?>

Provides a comparator of nullable Comparable values considering null value less than any other value.

Since Kotlin 1.0
fun <T : Any> nullsFirst(comparator: Comparator<in T>): Comparator<T?>

Extends the given comparator of non-nullable values to a comparator of nullable values considering null value less than any other value.

Since Kotlin 1.0
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inline fun <T : Comparable<T>> nullsLast(): Comparator<T?>

Provides a comparator of nullable Comparable values considering null value greater than any other value.

Since Kotlin 1.0
fun <T : Any> nullsLast(comparator: Comparator<in T>): Comparator<T?>

Extends the given comparator of non-nullable values to a comparator of nullable values considering null value greater than any other value.

Since Kotlin 1.0
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fun <T> Comparator<T>.reversed(): Comparator<T>

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

Since Kotlin 1.0
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fun <T : Comparable<T>> reverseOrder(): Comparator<T>

Returns a comparator that compares Comparable objects in reversed natural order.

Since Kotlin 1.0
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infix fun <T> Comparator<T>.then(comparator: Comparator<in T>): Comparator<T>

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

Since Kotlin 1.0
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inline fun <T> Comparator<T>.thenBy(crossinline selector: (T) -> Comparable<*>?): Comparator<T>

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.

Since Kotlin 1.0
inline fun <T, K> Comparator<T>.thenBy(comparator: Comparator<in K>, crossinline selector: (T) -> K): 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.

Since Kotlin 1.0
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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.

Since Kotlin 1.0
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.

Since Kotlin 1.0
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inline fun <T> Comparator<T>.thenComparator(crossinline comparison: (a: T, b: T) -> Int): Comparator<T>

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

Since Kotlin 1.0
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infix fun <T> Comparator<T>.thenDescending(comparator: Comparator<in T>): Comparator<T>

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

Since Kotlin 1.0