kitecore/io.github.yuroyami.kitecore.collections

Package-level declarations

Functions

allEqual

fun <T> Iterable<T>.allEqual(): Boolean

Returns true when every element equals the first one. An empty iterable returns true.

anyDuplicate

fun <T> Iterable<T>.anyDuplicate(): Boolean

Returns true if at least one element occurs more than once.

associateWithIndex

fun <T> Iterable<T>.associateWithIndex(): Map<T, Int>

Returns a map of each element to its index in this iterable.

cartesianProduct

fun <T, R> Iterable<T>.cartesianProduct(other: Iterable<R>): List<Pair<T, R>>

Returns every pairing of an element of this iterable with an element of other.

chunkedBy

inline fun <T, K> Iterable<T>.chunkedBy(selector: (T) -> K): List<List<T>>

Splits this iterable into consecutive runs, starting a new run whenever the value of selector changes.

countBy

inline fun <T, K> Iterable<T>.countBy(selector: (T) -> K): Map<K, Int>

Returns a map of each distinct value of selector to the number of elements producing it.

duplicates

fun <T> Iterable<T>.duplicates(): Set<T>

Returns the set of elements that occur more than once.

endsWith

fun <T> List<T>.endsWith(suffix: List<T>): Boolean

Returns true if this list ends with the elements of suffix in order.

filterKeysNotNull

fun <K : Any, V> Map<K?, V>.filterKeysNotNull(): Map<K, V>

Returns a map containing only the entries whose key is not null, with keys typed as non-null.

filterValuesNotNull

fun <K, V : Any> Map<K, V?>.filterValuesNotNull(): Map<K, V>

Returns a map containing only the entries whose value is not null, with values typed as non-null.

fourth

fun <T> List<T>.fourth(): T

Returns the fourth element.

fourthOrNull

fun <T> List<T>.fourthOrNull(): T?

Returns the fourth element, or null if the list has fewer than four elements.

frequencies

fun <T> Iterable<T>.frequencies(): Map<T, Int>

Returns a map of each distinct element to the number of times it occurs.

headAndTail

fun <T> List<T>.headAndTail(): Pair<T, List<T>>

Returns the first element paired with a list of the remaining elements.

headAndTailOrNull

fun <T> List<T>.headAndTailOrNull(): Pair<T, List<T>>?

Returns the first element paired with the remaining elements, or null if the list is empty.

indicesOf

fun <T> List<T>.indicesOf(element: T): List<Int>

Returns every index at which element occurs, in ascending order.

interleaved

fun <T> List<T>.interleaved(other: List<T>): List<T>

Returns a list alternating elements of this list and other, starting with this list.

inverted

fun <K, V> Map<K, V>.inverted(): Map<V, K>

Returns a map from each value to its key.

invertedAll

fun <K, V> Map<K, V>.invertedAll(): Map<V, List<K>>

Returns a map from each value to the list of all keys that map to it.

isDistinct

fun <T> Iterable<T>.isDistinct(): Boolean

Returns true if no element occurs more than once.

mapKeysNotNull

inline fun <K, V, R : Any> Map<K, V>.mapKeysNotNull(transform: (Map.Entry<K, V>) -> R?): Map<R, V>

Returns a map with each key replaced by the result of transform, dropping entries where it returns null.

mapToSet

inline fun <T, R> Iterable<T>.mapToSet(transform: (T) -> R): Set<R>

Returns a set of the results of applying transform to each element.

mapValuesNotNull

inline fun <K, V, R : Any> Map<K, V>.mapValuesNotNull(transform: (Map.Entry<K, V>) -> R?): Map<K, R>

Returns a map with each value replaced by the result of transform, dropping entries where it returns null.

median

fun List<Double>.median(): Double

@JvmName(name = "medianOfInt")

fun List<Int>.median(): Double

@JvmName(name = "medianOfLong")

fun List<Long>.median(): Double

Returns the median of this list.

medianOrNull

fun List<Double>.medianOrNull(): Double?

@JvmName(name = "medianOrNullOfInt")

fun List<Int>.medianOrNull(): Double?

@JvmName(name = "medianOrNullOfLong")

fun List<Long>.medianOrNull(): Double?

Returns the median of this list, or null if the list is empty.

mergedWith

inline fun <K, V> Map<K, V>.mergedWith(other: Map<K, V>, resolve: (key: K, current: V, incoming: V) -> V): Map<K, V>

Returns a map combining this map with other, calling resolve for keys present in both.

mergeWith

inline fun <K, V> MutableMap<K, V>.mergeWith(other: Map<K, V>, resolve: (key: K, current: V, incoming: V) -> V)

Merges other into this map in place, calling resolve for keys present in both.

middle

fun <T> List<T>.middle(): T

Returns the middle element, or the earlier of the two middle elements for even sizes.

middleOrNull

fun <T> List<T>.middleOrNull(): T?

Returns the middle element, or null when the list is empty. Even sizes use the earlier middle.

minMaxOrNull

fun <T : Comparable<T>> Iterable<T>.minMaxOrNull(): Pair<T, T>?

Returns the smallest and largest element as a pair, or null if the receiver is empty.

mode

fun <T> Iterable<T>.mode(): T?

Returns the most frequent element, or null if the receiver is empty.

move

fun <T> MutableList<T>.move(fromIndex: Int, toIndex: Int)

Moves the element at fromIndex so that it sits at toIndex, shifting the elements between them.

moved

fun <T> List<T>.moved(fromIndex: Int, toIndex: Int): List<T>

Returns a copy of this list with the element at fromIndex moved so that it sits at toIndex in the result.

padded

fun <T> List<T>.padded(size: Int, element: T): List<T>

Returns a copy of this list grown to size elements by appending element.

padTo

fun <T> MutableList<T>.padTo(size: Int, element: T)

Grows this list in place to size elements by appending element.

partitionIndexed

inline fun <T> Iterable<T>.partitionIndexed(predicate: (index: Int, T) -> Boolean): Pair<List<T>, List<T>>

Splits this iterable into a pair of lists using predicate, which also receives each element's index.

penultimate

fun <T> List<T>.penultimate(): T

Returns the element before the last one.

penultimateOrNull

fun <T> List<T>.penultimateOrNull(): T?

Returns the element before the last one, or null if the list has fewer than two elements.

percentile

fun List<Double>.percentile(p: Double): Double

@JvmName(name = "percentileOfInt")

fun List<Int>.percentile(p: Double): Double

@JvmName(name = "percentileOfLong")

fun List<Long>.percentile(p: Double): Double

Returns the p-th percentile of this list using linear interpolation between closest ranks.

percentileOrNull

fun List<Double>.percentileOrNull(p: Double): Double?

@JvmName(name = "percentileOrNullOfInt")

fun List<Int>.percentileOrNull(p: Double): Double?

@JvmName(name = "percentileOrNullOfLong")

fun List<Long>.percentileOrNull(p: Double): Double?

Returns the p-th percentile of this list, or null if the list is empty.

product

@JvmName(name = "productOfDouble")

fun Iterable<Double>.product(): Double

@JvmName(name = "productOfLong")

fun Iterable<Long>.product(): Long

Returns the product of all elements.

@JvmName(name = "productOfInt")

fun Iterable<Int>.product(): Long

Returns the product of all elements, accumulated as a Long.

removeFirstWhere

inline fun <T> MutableList<T>.removeFirstWhere(predicate: (T) -> Boolean): Boolean

Removes the first element matching predicate and returns true, or returns false if none matches.

removeLastWhere

inline fun <T> MutableList<T>.removeLastWhere(predicate: (T) -> Boolean): Boolean

Removes the last element matching predicate and returns true, or returns false if none matches.

repeated

fun <T> List<T>.repeated(times: Int): List<T>

Returns a list containing this list's elements repeated times times in sequence.

replacedAt

fun <T> List<T>.replacedAt(index: Int, element: T): List<T>

Returns a copy of this list with the element at index replaced by element.

rotate

fun <T> MutableList<T>.rotate(distance: Int)

Rotates this list in place by distance positions.

rotated

fun <T> List<T>.rotated(distance: Int): List<T>

Returns a copy of this list rotated by distance positions.

second

fun <T> List<T>.second(): T

Returns the second element.

secondOrNull

fun <T> List<T>.secondOrNull(): T?

Returns the second element, or null if the list has fewer than two elements.

splitAt

fun <T> List<T>.splitAt(index: Int): Pair<List<T>, List<T>>

Splits the list into the elements before index and the elements from index onward.

splitBy

inline fun <T> Iterable<T>.splitBy(isDelimiter: (T) -> Boolean): List<List<T>>

Splits this iterable into segments separated by elements matching isDelimiter, dropping the delimiters.

startsWith

fun <T> List<T>.startsWith(prefix: List<T>): Boolean

Returns true if this list begins with the elements of prefix in order.

stdDev

fun List<Double>.stdDev(): Double

@JvmName(name = "stdDevOfInt")

fun List<Int>.stdDev(): Double

@JvmName(name = "stdDevOfLong")

fun List<Long>.stdDev(): Double

Returns the population standard deviation of this list.

stdDevOrNull

fun List<Double>.stdDevOrNull(): Double?

@JvmName(name = "stdDevOrNullOfInt")

fun List<Int>.stdDevOrNull(): Double?

@JvmName(name = "stdDevOrNullOfLong")

fun List<Long>.stdDevOrNull(): Double?

Returns the population standard deviation of this list, or null if the list is empty.

swap

fun <T> MutableList<T>.swap(i: Int, j: Int)

Exchanges the elements at i and j in place.

swapped

fun <T> List<T>.swapped(i: Int, j: Int): List<T>

Returns a copy of this list with the elements at i and j exchanged.

takeIfNotEmpty

fun <C : Collection<*>> C.takeIfNotEmpty(): C?

Returns this collection if it is not empty, or null otherwise.

fun <M : Map<*, *>> M.takeIfNotEmpty(): M?

Returns this map if it is not empty, or null otherwise.

third

fun <T> List<T>.third(): T

Returns the third element.

thirdOrNull

fun <T> List<T>.thirdOrNull(): T?

Returns the third element, or null if the list has fewer than three elements.

toggle

fun <T> MutableSet<T>.toggle(element: T): Boolean

Adds element if absent or removes it if present, and returns whether the set contains it afterwards.

toggled

fun <T> Set<T>.toggled(element: T): Set<T>

Returns a copy of this set with element added if absent or removed if present.

transposed

fun <T> List<List<T>>.transposed(): List<List<T>>

Returns this list of rows transposed into a list of columns.

updateAt

inline fun <T> MutableList<T>.updateAt(index: Int, transform: (T) -> T)

Replaces the element at index with the result of applying transform to it.

variance

fun List<Double>.variance(): Double

@JvmName(name = "varianceOfInt")

fun List<Int>.variance(): Double

@JvmName(name = "varianceOfLong")

fun List<Long>.variance(): Double

Returns the population variance of this list.

varianceOrNull

fun List<Double>.varianceOrNull(): Double?

@JvmName(name = "varianceOrNullOfInt")

fun List<Int>.varianceOrNull(): Double?

@JvmName(name = "varianceOrNullOfLong")

fun List<Long>.varianceOrNull(): Double?

Returns the population variance of this list, or null if the list is empty.

zipWithNextCircular

fun <T> List<T>.zipWithNextCircular(): List<Pair<T, T>>

Returns each element paired with its successor, where the last element wraps around to the first.