DoubleList

Artifact: androidx.collection:collection

Added in 1.5.0

Kotlin |Java

public sealed class DoubleList

Known direct subclasses

MutableDoubleList

MutableDoubleList

MutableDoubleList is a MutableList-like collection for Double values.

DoubleList is a List-like collection for Double values. It allows retrieving the elements without boxing. DoubleList is always backed by a MutableDoubleList, its MutableList-like subclass. The purpose of this class is to avoid the performance overhead of auto-boxing due to generics since Collection classes all operate on objects.

This implementation is not thread-safe: if multiple threads access this container concurrently, and one or more threads modify the structure of the list (insertion or removal for instance), the calling code must provide the appropriate synchronization. It is also not safe to mutate during reentrancy -- in the middle of a forEach, for example. However, concurrent reads are safe.

Summary

Protected constructors
`DoubleList(int initialCapacity)`

Public methods
`final boolean`	`any()` Returns `true` if there's at least one element in the collection.
`final boolean`	`any(@NonNull Function1<@NonNull Double, @NonNull Boolean> predicate)` Returns `true` if any of the elements give a `true` return value for `predicate`.
`final int`	`binarySearch(int element, int fromIndex, int toIndex)` Searches this list the specified element in the range defined by `fromIndex` and `toIndex`.
`final boolean`	`contains(double element)` Returns `true` if the `DoubleList` contains `element` or `false` otherwise.
`final boolean`	`containsAll(@NonNull DoubleList elements)` Returns `true` if the `DoubleList` contains all elements in `elements` or `false` if one or more are missing.
`final int`	`count()` Returns the number of elements in this list.
`final int`	`count(@NonNull Function1<@NonNull Double, @NonNull Boolean> predicate)` Counts the number of elements matching `predicate`.
`final double`	`elementAt(@IntRange(from = 0) int index)` Returns the element at the given `index` or throws `IndexOutOfBoundsException` if the `index` is out of bounds of this collection.
`final double`	`elementAtOrElse( @IntRange(from = 0) int index, @NonNull Function1<@NonNull Integer, @NonNull Double> defaultValue )` Returns the element at the given `index` or `defaultValue` if `index` is out of bounds of the collection.
`boolean`	`equals(Object other)` Returns `true` if `other` is a `DoubleList` and the contents of this and `other` are the same.
`final double`	`first()` Returns the first element in the `DoubleList` or throws a `NoSuchElementException` if it `isEmpty`.
`final double`	`first(@NonNull Function1<@NonNull Double, @NonNull Boolean> predicate)` Returns the first element in the `DoubleList` for which `predicate` returns `true` or throws `NoSuchElementException` if nothing matches.
`final @NonNull R`	`<R extends Object> fold( @NonNull R initial, @NonNull Function2<@NonNull acc, @NonNull Double, @NonNull R> operation )` Accumulates values, starting with `initial`, and applying `operation` to each element in the `DoubleList` in order.
`final @NonNull R`	`<R extends Object> foldIndexed( @NonNull R initial, @NonNull Function3<@NonNull Integer, @NonNull acc, @NonNull Double, @NonNull R> operation )` Accumulates values, starting with `initial`, and applying `operation` to each element in the `DoubleList` in order.
`final @NonNull R`	`<R extends Object> foldRight( @NonNull R initial, @NonNull Function2<@NonNull Double, @NonNull acc, @NonNull R> operation )` Accumulates values, starting with `initial`, and applying `operation` to each element in the `DoubleList` in reverse order.
`final @NonNull R`	`<R extends Object> foldRightIndexed( @NonNull R initial, @NonNull Function3<@NonNull Integer, @NonNull Double, @NonNull acc, @NonNull R> operation )` Accumulates values, starting with `initial`, and applying `operation` to each element in the `DoubleList` in reverse order.
`final void`	`forEach(@NonNull Function1<@NonNull Double, Unit> block)` Calls `block` for each element in the `DoubleList`, in order.
`final void`	`forEachIndexed( @NonNull Function2<@NonNull Integer, @NonNull Double, Unit> block )` Calls `block` for each element in the `DoubleList` along with its index, in order.
`final void`	`forEachReversed(@NonNull Function1<@NonNull Double, Unit> block)` Calls `block` for each element in the `DoubleList` in reverse order.
`final void`	`forEachReversedIndexed( @NonNull Function2<@NonNull Integer, @NonNull Double, Unit> block )` Calls `block` for each element in the `DoubleList` along with its index, in reverse order.
`final double`	`get(@IntRange(from = 0) int index)` Returns the element at the given `index` or throws `IndexOutOfBoundsException` if the `index` is out of bounds of this collection.
`final @NonNull IntRange`	`getIndices()` Returns an `IntRange` of the valid indices for this `DoubleList`.
`final @IntRange(from = -1) int`	`getLastIndex()` Returns the last valid index in the `DoubleList`.
`final @IntRange(from = 0) int`	`getSize()` The number of elements in the `DoubleList`.
`int`	`hashCode()` Returns a hash code based on the contents of the `DoubleList`.
`final int`	`indexOf(double element)` Returns the index of `element` in the `DoubleList` or `-1` if `element` is not there.
`final int`	`indexOfFirst( @NonNull Function1<@NonNull Double, @NonNull Boolean> predicate )` Returns the index if the first element in the `DoubleList` for which `predicate` returns `true`.
`final int`	`indexOfLast(@NonNull Function1<@NonNull Double, @NonNull Boolean> predicate)` Returns the index if the last element in the `DoubleList` for which `predicate` returns `true`.
`final boolean`	`isEmpty()` Returns `true` if the `DoubleList` has no elements in it or `false` otherwise.
`final boolean`	`isNotEmpty()` Returns `true` if there are elements in the `DoubleList` or `false` if it is empty.
`final @NonNull String`	`joinToString( @NonNull CharSequence separator, @NonNull CharSequence prefix, @NonNull CharSequence postfix, int limit, @NonNull CharSequence truncated )` Creates a String from the elements separated by `separator` and using `prefix` before and `postfix` after, if supplied.
`final @NonNull String`	`joinToString( @NonNull CharSequence separator, @NonNull CharSequence prefix, @NonNull CharSequence postfix, int limit, @NonNull CharSequence truncated, @NonNull Function1<@NonNull Double, @NonNull CharSequence> transform )` Creates a String from the elements separated by `separator` and using `prefix` before and `postfix` after, if supplied.
`final double`	`last()` Returns the last element in the `DoubleList` or throws a `NoSuchElementException` if it `isEmpty`.
`final double`	`last(@NonNull Function1<@NonNull Double, @NonNull Boolean> predicate)` Returns the last element in the `DoubleList` for which `predicate` returns `true` or throws `NoSuchElementException` if nothing matches.
`final int`	`lastIndexOf(double element)` Returns the index of the last element in the `DoubleList` that is the same as `element` or `-1` if no elements match.
`final boolean`	`none()` Returns `true` if the collection has no elements in it.
`final boolean`	`reversedAny(@NonNull Function1<@NonNull Double, @NonNull Boolean> predicate)` Returns `true` if any of the elements give a `true` return value for `predicate` while iterating in the reverse order.
`@NonNull String`	`toString()` Returns a String representation of the list, surrounded by "[]" and each element separated by ", ".

Protected constructors

DoubleList

protected DoubleList(int initialCapacity)

Public methods

any

Added in 1.5.0

public final boolean any()

Returns true if there's at least one element in the collection.

any

Added in 1.5.0

public final boolean any(@NonNull Function1<@NonNull Double, @NonNull Boolean> predicate)

Returns true if any of the elements give a true return value for predicate.

binarySearch

Added in 1.5.0

public final int binarySearch(int element, int fromIndex, int toIndex)

Searches this list the specified element in the range defined by fromIndex and toIndex. The list is expected to be sorted into ascending order according to the natural ordering of its elements, otherwise the result is undefined.

fromIndex must be >= 0 and <toIndex, and toIndex must be <= size, otherwise an an IndexOutOfBoundsException will be thrown.

Returns
`int`	the index of the element if it is contained in the list within the specified range. otherwise, the inverted insertion point `(-insertionPoint - 1)`. The insertion point is defined as the index at which the element should be inserted, so that the list remains sorted.

contains

Added in 1.5.0

public final boolean contains(double element)

Returns true if the DoubleList contains element or false otherwise.

containsAll

Added in 1.5.0

public final boolean containsAll(@NonNull DoubleList elements)

Returns true if the DoubleList contains all elements in elements or false if one or more are missing.

count

Added in 1.5.0

public final int count()

Returns the number of elements in this list.

count

Added in 1.5.0

public final int count(@NonNull Function1<@NonNull Double, @NonNull Boolean> predicate)

Counts the number of elements matching predicate.

Returns
`int`	The number of elements in this list for which `predicate` returns true.

elementAt

Added in 1.5.0

public final double elementAt(@IntRange(from = 0) int index)

Returns the element at the given index or throws IndexOutOfBoundsException if the index is out of bounds of this collection.

elementAtOrElse

Added in 1.5.0

public final double elementAtOrElse(
    @IntRange(from = 0) int index,
    @NonNull Function1<@NonNull Integer, @NonNull Double> defaultValue
)

Returns the element at the given index or defaultValue if index is out of bounds of the collection.

Parameters
`index: int`	The index of the element whose value should be returned
`@NonNull Function1<@NonNull Integer, @NonNull Double> defaultValue`	A lambda to call with `index` as a parameter to return a value at an index not in the list.

equals

public boolean equals(Object other)

Returns true if other is a DoubleList and the contents of this and other are the same.

first

Added in 1.5.0

public final double first()

Returns the first element in the DoubleList or throws a NoSuchElementException if it isEmpty.

first

Added in 1.5.0

public final double first(@NonNull Function1<@NonNull Double, @NonNull Boolean> predicate)

Returns the first element in the DoubleList for which predicate returns true or throws NoSuchElementException if nothing matches.

See also
`indexOfFirst`

fold

Added in 1.5.0

public final @NonNull R <R extends Object> fold(
    @NonNull R initial,
    @NonNull Function2<@NonNull acc, @NonNull Double, @NonNull R> operation
)

Accumulates values, starting with initial, and applying operation to each element in the DoubleList in order.

Parameters
`@NonNull R initial`	The value of `acc` for the first call to `operation` or return value if there are no elements in this list.
`@NonNull Function2<@NonNull acc, @NonNull Double, @NonNull R> operation`	function that takes current accumulator value and an element, and calculates the next accumulator value.

foldIndexed

Added in 1.5.0

public final @NonNull R <R extends Object> foldIndexed(
    @NonNull R initial,
    @NonNull Function3<@NonNull Integer, @NonNull acc, @NonNull Double, @NonNull R> operation
)

Accumulates values, starting with initial, and applying operation to each element in the DoubleList in order.

foldRight

Added in 1.5.0

public final @NonNull R <R extends Object> foldRight(
    @NonNull R initial,
    @NonNull Function2<@NonNull Double, @NonNull acc, @NonNull R> operation
)

Accumulates values, starting with initial, and applying operation to each element in the DoubleList in reverse order.

Parameters
`@NonNull R initial`	The value of `acc` for the first call to `operation` or return value if there are no elements in this list.
`@NonNull Function2<@NonNull Double, @NonNull acc, @NonNull R> operation`	function that takes an element and the current accumulator value, and calculates the next accumulator value.

foldRightIndexed

Added in 1.5.0

public final @NonNull R <R extends Object> foldRightIndexed(
    @NonNull R initial,
    @NonNull Function3<@NonNull Integer, @NonNull Double, @NonNull acc, @NonNull R> operation
)

Accumulates values, starting with initial, and applying operation to each element in the DoubleList in reverse order.

forEach

Added in 1.5.0

public final void forEach(@NonNull Function1<@NonNull Double, Unit> block)

Calls block for each element in the DoubleList, in order.

Parameters
`@NonNull Function1<@NonNull Double, Unit> block`	will be executed for every element in the list, accepting an element from the list

forEachIndexed

Added in 1.5.0

public final void forEachIndexed(
    @NonNull Function2<@NonNull Integer, @NonNull Double, Unit> block
)

Calls block for each element in the DoubleList along with its index, in order.

Parameters
`@NonNull Function2<@NonNull Integer, @NonNull Double, Unit> block`	will be executed for every element in the list, accepting the index and the element at that index.

forEachReversed

Added in 1.5.0

public final void forEachReversed(@NonNull Function1<@NonNull Double, Unit> block)

Calls block for each element in the DoubleList in reverse order.

Parameters
`@NonNull Function1<@NonNull Double, Unit> block`	will be executed for every element in the list, accepting an element from the list

forEachReversedIndexed

Added in 1.5.0

public final void forEachReversedIndexed(
    @NonNull Function2<@NonNull Integer, @NonNull Double, Unit> block
)

Calls block for each element in the DoubleList along with its index, in reverse order.

Parameters
`@NonNull Function2<@NonNull Integer, @NonNull Double, Unit> block`	will be executed for every element in the list, accepting the index and the element at that index.

get

Added in 1.5.0

public final double get(@IntRange(from = 0) int index)

Returns the element at the given index or throws IndexOutOfBoundsException if the index is out of bounds of this collection.

getIndices

Added in 1.5.0

public final @NonNull IntRange getIndices()

Returns an IntRange of the valid indices for this DoubleList.

getLastIndex

Added in 1.5.0

public final @IntRange(from = -1) int getLastIndex()

Returns the last valid index in the DoubleList. This can be -1 when the list is empty.

getSize

Added in 1.5.0

public final @IntRange(from = 0) int getSize()

The number of elements in the DoubleList.

hashCode

public int hashCode()

Returns a hash code based on the contents of the DoubleList.

indexOf

Added in 1.5.0

public final int indexOf(double element)

Returns the index of element in the DoubleList or -1 if element is not there.

indexOfFirst

Added in 1.5.0

public final int indexOfFirst(
    @NonNull Function1<@NonNull Double, @NonNull Boolean> predicate
)

Returns the index if the first element in the DoubleList for which predicate returns true.

indexOfLast

Added in 1.5.0

public final int indexOfLast(@NonNull Function1<@NonNull Double, @NonNull Boolean> predicate)

Returns the index if the last element in the DoubleList for which predicate returns true.

isEmpty

Added in 1.5.0

public final boolean isEmpty()

Returns true if the DoubleList has no elements in it or false otherwise.

isNotEmpty

Added in 1.5.0

public final boolean isNotEmpty()

Returns true if there are elements in the DoubleList or false if it is empty.

joinToString

Added in 1.5.0

public final @NonNull String joinToString(
    @NonNull CharSequence separator,
    @NonNull CharSequence prefix,
    @NonNull CharSequence postfix,
    int limit,
    @NonNull CharSequence truncated
)

Creates a String from the elements separated by separator and using prefix before and postfix after, if supplied.

When a non-negative value of limit is provided, a maximum of limit items are used to generate the string. If the collection holds more than limit items, the string is terminated with truncated.

joinToString

public final @NonNull String joinToString(
    @NonNull CharSequence separator,
    @NonNull CharSequence prefix,
    @NonNull CharSequence postfix,
    int limit,
    @NonNull CharSequence truncated,
    @NonNull Function1<@NonNull Double, @NonNull CharSequence> transform
)

Creates a String from the elements separated by separator and using prefix before and postfix after, if supplied. transform dictates how each element will be represented.

last

Added in 1.5.0

public final double last()

Returns the last element in the DoubleList or throws a NoSuchElementException if it isEmpty.

last

Added in 1.5.0

public final double last(@NonNull Function1<@NonNull Double, @NonNull Boolean> predicate)

Returns the last element in the DoubleList for which predicate returns true or throws NoSuchElementException if nothing matches.

See also
`indexOfLast`

lastIndexOf

Added in 1.5.0

public final int lastIndexOf(double element)

Returns the index of the last element in the DoubleList that is the same as element or -1 if no elements match.

none

Added in 1.5.0

public final boolean none()

Returns true if the collection has no elements in it.

reversedAny

Added in 1.5.0

public final boolean reversedAny(@NonNull Function1<@NonNull Double, @NonNull Boolean> predicate)

Returns true if any of the elements give a true return value for predicate while iterating in the reverse order.

toString

public @NonNull String toString()

Returns a String representation of the list, surrounded by "[]" and each element separated by ", ".