Interface IndexedSeq<T>

Type Parameters:

T - the element type

All Superinterfaces:

Foldable<T>, Function<Integer,T>, Function1<Integer,T>, Iterable<T>, PartialFunction<Integer,T>, Seq<T>, Serializable, Traversable<T>, Value<T>

All Known Implementing Classes:

Array, CharSeq, Vector

public interface IndexedSeq<T>
extends Seq<T>

Represents an immutable, indexed sequence of elements.

Indexed sequences provide efficient random access and preserve element order.

Field Summary

Fields

Modifier and Type	Field	Description
static final long	serialVersionUID	The serial version UID for serialization.

Method Summary

Modifier and Type	Method	Description
IndexedSeq<T>	append(T element)	Returns a new sequence with the given element appended at the end.
IndexedSeq<T>	appendAll(@NonNull Iterable<? extends T> elements)	Returns a new sequence with all elements from the given Iterable appended at the end of this sequence.
IndexedSeq<T>	asJava(@NonNull Consumer<? super List<T>> action)	Creates an immutable List view of this Seq and passes it to the given action.
IndexedSeq<T>	asJavaMutable(@NonNull Consumer<? super List<T>> action)	Creates a mutable List view of this Seq and passes it to the given action.
default PartialFunction<Integer,T>	asPartialFunction()	Returns a PartialFunction view of this Seq, where the function is defined at an index if this sequence contains at least index + 1 elements.
<R> IndexedSeq<R>	collect(@NonNull PartialFunction<? super T, ? extends R> partialFunction)	Applies a PartialFunction to all elements that are defined for it and collects the results.
IndexedSeq<? extends IndexedSeq<T>>	combinations()	Returns a sequence containing all combinations of elements from this sequence, for all sizes from 0 to length().
IndexedSeq<? extends IndexedSeq<T>>	combinations(int k)	Returns all subsets of this sequence containing exactly k distinct elements, i.e., the k-combinations of this sequence.
Iterator<? extends IndexedSeq<T>>	crossProduct(int power)	Returns the n-ary Cartesian power (cross product) of this sequence.
IndexedSeq<T>	distinct()	Returns a new Traversable containing the elements of this instance with all duplicates removed.
IndexedSeq<T>	distinctBy(@NonNull Comparator<? super T> comparator)	Returns a new Traversable containing the elements of this instance without duplicates, as determined by the given comparator.
<U> IndexedSeq<T>	distinctBy(@NonNull Function<? super T, ? extends U> keyExtractor)	Returns a new Traversable containing the elements of this instance without duplicates, based on keys extracted from elements using keyExtractor.
IndexedSeq<T>	distinctByKeepLast(@NonNull Comparator<? super T> comparator)	Returns a sequence with duplicate elements removed, as determined by the provided comparator.
<U> IndexedSeq<T>	distinctByKeepLast(@NonNull Function<? super T, ? extends U> keyExtractor)	Returns a sequence with duplicates removed based on a key extracted from each element.
IndexedSeq<T>	drop(int n)	Returns a new Traversable without the first n elements, or an empty instance if this contains fewer than n elements.
IndexedSeq<T>	dropRight(int n)	Returns a new Traversable without the last n elements, or an empty instance if this contains fewer than n elements.
IndexedSeq<T>	dropRightUntil(@NonNull Predicate<? super T> predicate)	Drops elements from the end of the sequence until an element satisfies the given predicate.
IndexedSeq<T>	dropRightWhile(@NonNull Predicate<? super T> predicate)	Drops elements from the end of the sequence while the given predicate holds.
IndexedSeq<T>	dropUntil(@NonNull Predicate<? super T> predicate)	Returns a new Traversable starting from the first element that satisfies the given predicate, dropping all preceding elements.
IndexedSeq<T>	dropWhile(@NonNull Predicate<? super T> predicate)	Returns a new Traversable starting from the first element that does not satisfy the given predicate, dropping all preceding elements.
default boolean	endsWith(@NonNull Seq<? extends T> that)	Checks whether this sequence ends with the given sequence.
IndexedSeq<T>	filter(@NonNull Predicate<? super T> predicate)	Returns a new traversable containing only the elements that satisfy the given predicate.
<U> IndexedSeq<U>	flatMap(@NonNull Function<? super T, ? extends Iterable<? extends U>> mapper)	Transforms each element of this Traversable into an Iterable of elements and flattens the resulting iterables into a single Traversable.
<C> Map<C, ? extends IndexedSeq<T>>	groupBy(@NonNull Function<? super T, ? extends C> classifier)	Groups elements of this Traversable based on a classifier function.
Iterator<? extends IndexedSeq<T>>	grouped(int size)	Splits this Traversable into consecutive blocks of the given size.
default int	indexOfSlice(@NonNull Iterable<? extends T> that, int from)	Returns the first index at or after the specified start index where this sequence contains the given sequence as a contiguous slice, or -1 if no such slice exists.
default int	indexWhere(@NonNull Predicate<? super T> predicate, int from)	Returns the index of the first element at or after the specified start index that satisfies the given predicate, or -1 if no such element exists.
IndexedSeq<T>	init()	Returns all elements of this Traversable except the last one.
Option<? extends IndexedSeq<T>>	initOption()	Returns all elements of this Traversable except the last one, wrapped in an Option.
IndexedSeq<T>	insert(int index, T element)	Returns a new sequence with the given element inserted at the specified index.
IndexedSeq<T>	insertAll(int index, @NonNull Iterable<? extends T> elements)	Returns a new sequence with the given elements inserted at the specified index.
IndexedSeq<T>	intersperse(T element)	Returns a new sequence where the given element is inserted between all elements of this sequence.
default boolean	isDefinedAt(Integer index)	Deprecated.
default T	last()	Returns the last element of this Traversable.
default int	lastIndexOfSlice(@NonNull Iterable<? extends T> that, int end)	Returns the last index at or before the specified end index where this sequence contains the given sequence as a contiguous slice, or -1 if no such slice exists.
default int	lastIndexWhere(@NonNull Predicate<? super T> predicate, int end)	Returns the index of the last element at or before the specified end index that satisfies the given predicate, or -1 if no such element exists.
<U> IndexedSeq<U>	map(@NonNull Function<? super T, ? extends U> mapper)	Transforms the elements of this Traversable to a new type, preserving order if defined.
default <U> IndexedSeq<U>	mapTo(U value)	Maps the underlying value to another fixed value.
default IndexedSeq<Void>	mapToVoid()	Maps the underlying value to Void
static <T> IndexedSeq<T>	narrow(IndexedSeq<? extends T> indexedSeq)	Narrows a widened IndexedSeq<? extends T> to IndexedSeq<T>.
IndexedSeq<T>	orElse(Iterable<? extends T> other)	Returns this Traversable if it is non-empty; otherwise, returns the given alternative.
IndexedSeq<T>	orElse(@NonNull Supplier<? extends Iterable<? extends T>> supplier)	Returns this Traversable if it is non-empty; otherwise, returns the result of evaluating the given supplier.
IndexedSeq<T>	padTo(int length, T element)	Returns a new sequence with this sequence padded on the right with the given element until the specified target length is reached.
Tuple2<? extends IndexedSeq<T>, ? extends IndexedSeq<T>>	partition(@NonNull Predicate<? super T> predicate)	Splits this Traversable into two partitions according to a predicate.
IndexedSeq<T>	patch(int from, @NonNull Iterable<? extends T> that, int replaced)	Returns a new sequence in which a slice of elements in this sequence is replaced by the elements of another sequence.
IndexedSeq<T>	peek(@NonNull Consumer<? super T> action)	Performs the given action on the first element if this is an eager implementation.
IndexedSeq<? extends IndexedSeq<T>>	permutations()	Returns all unique permutations of this sequence.
IndexedSeq<T>	prepend(T element)	Returns a new sequence with the given element prepended to this sequence.
IndexedSeq<T>	prependAll(@NonNull Iterable<? extends T> elements)	Returns a new sequence with all given elements prepended to this sequence.
IndexedSeq<T>	reject(@NonNull Predicate<? super T> predicate)	Returns a new traversable containing only the elements that do not satisfy the given predicate.
IndexedSeq<T>	remove(T element)	Returns a new sequence with the first occurrence of the given element removed.
IndexedSeq<T>	removeAll(@NonNull Iterable<? extends T> elements)	Returns a new sequence with all occurrences of the given elements removed.
IndexedSeq<T>	removeAll(@NonNull Predicate<? super T> predicate)	Deprecated.
IndexedSeq<T>	removeAll(T element)	Returns a new sequence with all occurrences of the given element removed.
IndexedSeq<T>	removeAt(int index)	Returns a new sequence with the element at the specified position removed.
IndexedSeq<T>	removeFirst(@NonNull Predicate<T> predicate)	Returns a new sequence with the first element that satisfies the given predicate removed.
IndexedSeq<T>	removeLast(@NonNull Predicate<T> predicate)	Returns a new sequence with the last element that satisfies the given predicate removed.
IndexedSeq<T>	replace(T currentElement, T newElement)	Replaces the first occurrence of currentElement with newElement, if it exists.
IndexedSeq<T>	replaceAll(T currentElement, T newElement)	Replaces all occurrences of currentElement with newElement.
IndexedSeq<T>	retainAll(@NonNull Iterable<? extends T> elements)	Retains only the elements from this Traversable that are contained in the given elements.
IndexedSeq<T>	reverse()	Returns a new sequence with the order of elements reversed.
default Iterator<T>	reverseIterator()	Returns an iterator that yields elements of this sequence in reversed order.
IndexedSeq<T>	rotateLeft(int n)	Returns a new sequence with the elements circularly rotated to the left by the specified distance.
IndexedSeq<T>	rotateRight(int n)	Returns a new sequence with the elements circularly rotated to the right by the specified distance.
IndexedSeq<T>	scan(T zero, @NonNull BiFunction<? super T, ? super T, ? extends T> operation)	Computes a prefix scan of the elements of this Traversable.
<U> IndexedSeq<U>	scanLeft(U zero, @NonNull BiFunction<? super U, ? super T, ? extends U> operation)	Produces a collection containing cumulative results of applying the operator from left to right.
<U> IndexedSeq<U>	scanRight(U zero, @NonNull BiFunction<? super T, ? super U, ? extends U> operation)	Produces a collection containing cumulative results of applying the operator from right to left.
default int	search(T element)	Searches this sequence for a specific element using a binary search.
default int	search(T element, @NonNull Comparator<? super T> comparator)	Searches this sequence for a specific element using a binary search.
default int	segmentLength(@NonNull Predicate<? super T> predicate, int from)	Returns the length of the longest contiguous segment, starting from the specified index, in which all elements satisfy the given predicate.
IndexedSeq<T>	shuffle()	Returns a new sequence with the elements randomly shuffled.
IndexedSeq<T>	slice(int beginIndex, int endIndex)	Returns a subsequence (slice) of this sequence, starting at beginIndex (inclusive) and ending at endIndex (exclusive).
Iterator<? extends IndexedSeq<T>>	slideBy(@NonNull Function<? super T, ?> classifier)	Partitions this Traversable into consecutive non-overlapping windows according to a classification function.
Iterator<? extends IndexedSeq<T>>	sliding(int size)	Slides a window of a given size over this Traversable with a step size of 1.
Iterator<? extends IndexedSeq<T>>	sliding(int size, int step)	Slides a window of a specific size with a given step over this Traversable.
<U> IndexedSeq<T>	sortBy(@NonNull Comparator<? super U> comparator, Function<? super T, ? extends U> mapper)	Returns a new sequence sorted by comparing elements in a different domain defined by the given mapper, using the provided comparator.
<U extends Comparable<? super U>> IndexedSeq<T>	sortBy(@NonNull Function<? super T, ? extends U> mapper)	Returns a new sequence sorted by comparing elements in a different domain defined by the given mapper.
IndexedSeq<T>	sorted()	Returns a new sequence with elements sorted according to their natural order.
IndexedSeq<T>	sorted(@NonNull Comparator<? super T> comparator)	Returns a new sequence with elements sorted according to the given Comparator.
Tuple2<? extends IndexedSeq<T>, ? extends IndexedSeq<T>>	span(@NonNull Predicate<? super T> predicate)	Splits this Traversable into a prefix and remainder according to the given predicate.
default boolean	startsWith(@NonNull Iterable<? extends T> that, int offset)	Tests whether this sequence contains the given sequence starting at the specified index.
IndexedSeq<T>	subSequence(int beginIndex)	Returns a Seq that is a subsequence of this sequence, starting from the specified beginIndex and extending to the end of this sequence.
IndexedSeq<T>	subSequence(int beginIndex, int endIndex)	Returns a Seq that is a subsequence of this sequence, starting from the specified beginIndex (inclusive) and ending at endIndex (exclusive).
IndexedSeq<T>	tail()	Returns a new Traversable without its first element.
Option<? extends IndexedSeq<T>>	tailOption()	Returns a new Traversable without its first element as an Option.
IndexedSeq<T>	take(int n)	Returns the first n elements of this Traversable, or all elements if n exceeds the length.
IndexedSeq<T>	takeRight(int n)	Returns the last n elements of this Traversable, or all elements if n exceeds the length.
IndexedSeq<T>	takeRightUntil(@NonNull Predicate<? super T> predicate)	Takes elements from the end of the sequence until an element satisfies the given predicate.
IndexedSeq<T>	takeRightWhile(@NonNull Predicate<? super T> predicate)	Takes elements from the end of the sequence while the given predicate holds.
IndexedSeq<T>	takeUntil(@NonNull Predicate<? super T> predicate)	Takes elements from this Traversable until the given predicate holds for an element.
IndexedSeq<T>	takeWhile(@NonNull Predicate<? super T> predicate)	Takes elements from this Traversable while the given predicate holds.
<T1,T2> Tuple2<? extends IndexedSeq<T1>, ? extends IndexedSeq<T2>>	unzip(@NonNull Function<? super T, Tuple2<? extends T1, ? extends T2>> unzipper)	Unzips the elements of this Traversable by mapping each element to a pair and splitting them into two separate Traversable collections.
<T1,T2,T3> Tuple3<? extends IndexedSeq<T1>, ? extends IndexedSeq<T2>, ? extends IndexedSeq<T3>>	unzip3(@NonNull Function<? super T, Tuple3<? extends T1, ? extends T2, ? extends T3>> unzipper)	Unzips the elements of this Traversable by mapping each element to a triple and splitting them into three separate Traversable collections.
IndexedSeq<T>	update(int index, @NonNull Function<? super T, ? extends T> updater)	Returns a new Seq with the element at the specified index updated using the given function.
IndexedSeq<T>	update(int index, T element)	Returns a new Seq with the element at the specified index replaced by the given value.
<U> IndexedSeq<Tuple2<T,U>>	zip(@NonNull Iterable<? extends U> that)	Returns a Traversable formed by pairing elements of this Traversable with elements of another Iterable.
<U> IndexedSeq<Tuple2<T,U>>	zipAll(@NonNull Iterable<? extends U> that, T thisElem, U thatElem)	Returns a Traversable formed by pairing elements of this Traversable with elements of another Iterable, filling in placeholder elements when one collection is shorter than the other.
<U,R> IndexedSeq<R>	zipWith(@NonNull Iterable<? extends U> that, BiFunction<? super T, ? super U, ? extends R> mapper)	Returns a Traversable by combining elements of this Traversable with elements of another Iterable using a mapping function.
IndexedSeq<Tuple2<T,Integer>>	zipWithIndex()	Zips this Traversable with its indices, starting at 0.
<U> IndexedSeq<U>	zipWithIndex(@NonNull BiFunction<? super T, ? super Integer, ? extends U> mapper)	Zips this Traversable with its indices and maps the resulting pairs using the provided mapper.

Methods inherited from interface Foldable

fold, reduce, reduceOption

Methods inherited from interface Function1

andThen, arity, compose, compose1, curried, isMemoized, memoized, partial, reversed, tupled

Methods inherited from interface Seq

apply, asJava, asJavaMutable, containsSlice, crossProduct, crossProduct, foldRight, get, indexOf, indexOf, indexOfOption, indexOfOption, indexOfSlice, indexOfSliceOption, indexOfSliceOption, indexWhere, indexWhereOption, indexWhereOption, isSequential, iterator, lastIndexOf, lastIndexOf, lastIndexOfOption, lastIndexOfOption, lastIndexOfSlice, lastIndexOfSliceOption, lastIndexOfSliceOption, lastIndexWhere, lastIndexWhereOption, lastIndexWhereOption, leftPadTo, lift, prefixLength, splitAt, splitAt, splitAtInclusive, startsWith, withDefault, withDefaultValue

Methods inherited from interface Traversable

arrangeBy, average, containsAll, count, equals, existsUnique, find, findLast, foldLeft, forEachWithIndex, get, hasDefiniteSize, hashCode, head, headOption, isDistinct, isEmpty, isOrdered, isSingleValued, isTraversableAgain, iterator, lastOption, length, max, maxBy, maxBy, min, minBy, minBy, mkCharSeq, mkCharSeq, mkCharSeq, mkString, mkString, mkString, nonEmpty, product, reduceLeft, reduceLeftOption, reduceRight, reduceRightOption, single, singleOption, size, spliterator, sum

Methods inherited from interface Value

collect, collect, contains, corresponds, eq, exists, forAll, forEach, getOrElse, getOrElse, getOrElseThrow, getOrElseTry, getOrNull, isAsync, isLazy, out, out, stderr, stdout, stringPrefix, toArray, toCharSeq, toCompletableFuture, toEither, toEither, toInvalid, toInvalid, toJavaArray, toJavaArray, toJavaArray, toJavaCollection, toJavaList, toJavaList, toJavaMap, toJavaMap, toJavaMap, toJavaOptional, toJavaParallelStream, toJavaSet, toJavaSet, toJavaStream, toLeft, toLeft, toLinkedMap, toLinkedMap, toLinkedSet, toList, toMap, toMap, toOption, toPriorityQueue, toPriorityQueue, toQueue, toRight, toRight, toSet, toSortedMap, toSortedMap, toSortedMap, toSortedMap, toSortedSet, toSortedSet, toStream, toString, toTree, toTree, toTry, toTry, toValid, toValid, toValidation, toValidation, toVector

Field Details

serialVersionUID

static final long serialVersionUID

The serial version UID for serialization.

See Also:

• Constant Field Values

Method Details

narrow

static <T> IndexedSeq<T> narrow(IndexedSeq<? extends T> indexedSeq)

Narrows a widened IndexedSeq<? extends T> to IndexedSeq<T>.

This is safe for immutable, read-only sequences, which are covariant.

Type Parameters:

T - the target element type

Parameters:

indexedSeq - an IndexedSeq instance

Returns:

the same IndexedSeq instance with the narrowed type

append

IndexedSeq<T> append(T element)

Description copied from interface: Seq

Returns a new sequence with the given element appended at the end.

Specified by:

append in interface Seq<T>

Parameters:

element - the element to append

Returns:

a new Seq containing all elements of this sequence followed by the given element

appendAll

IndexedSeq<T> appendAll(@NonNull Iterable<? extends T> elements)

Description copied from interface: Seq

Returns a new sequence with all elements from the given Iterable appended at the end of this sequence.

Specified by:

appendAll in interface Seq<T>

Parameters:

elements - the elements to append; must not be null

Returns:

a new Seq containing all elements of this sequence followed by the given elements

asJava

@GwtIncompatible
IndexedSeq<T> asJava(@NonNull Consumer<? super List<T>> action)

Description copied from interface: Seq

Creates an immutable List view of this Seq and passes it to the given action.

The view is immutable: any attempt to modify it will throw UnsupportedOperationException at runtime.

Specified by:

asJava in interface Seq<T>

Parameters:

action - a side-effecting operation that receives an immutable java.util.List view

Returns:

this sequence

See Also:

• Seq.asJava()

asJavaMutable

@GwtIncompatible
IndexedSeq<T> asJavaMutable(@NonNull Consumer<? super List<T>> action)

Description copied from interface: Seq

Creates a mutable List view of this Seq and passes it to the given action.

The view supports all standard mutator methods. The result of the action determines what is returned:

• If only read operations are performed, this instance is returned.
• If any write operations are performed, a new Seq reflecting those changes is returned.

Specified by:

asJavaMutable in interface Seq<T>

Parameters:

action - a side-effecting operation that receives a mutable java.util.List view

Returns:

this sequence or a new sequence reflecting modifications made through the view

See Also:

• Seq.asJavaMutable()

asPartialFunction

default PartialFunction<Integer,T> asPartialFunction()
                                              throws IndexOutOfBoundsException

Description copied from interface: Seq

Returns a PartialFunction view of this Seq, where the function is defined at an index if this sequence contains at least index + 1 elements. Applying the partial function to a defined index returns the element at that index.

Specified by:

asPartialFunction in interface Seq<T>

Returns:

a PartialFunction mapping indices to elements

Throws:

IndexOutOfBoundsException - if the sequence is empty, or if index < 0 or index >= length()

collect

<R> IndexedSeq<R> collect(@NonNull PartialFunction<? super T, ? extends R> partialFunction)

Description copied from interface: Traversable

Applies a PartialFunction to all elements that are defined for it and collects the results.

For each element in iteration order, the function is first tested:

partialFunction.isDefinedAt(element)

If true, the element is mapped to type R:

R newElement = partialFunction.apply(element)

Note: If this Traversable is ordered (i.e., extends Ordered), the caller must ensure that the resulting elements are comparable (i.e., implement Comparable).

Specified by:

collect in interface Seq<T>

Specified by:

collect in interface Traversable<T>

Type Parameters:

R - the type of elements in the resulting Traversable

Parameters:

partialFunction - a function that may not be defined for all elements of this traversable

Returns:

a new Traversable containing the results of applying the partial function

combinations

IndexedSeq<? extends IndexedSeq<T>> combinations()

Description copied from interface: Seq

Returns a sequence containing all combinations of elements from this sequence, for all sizes from 0 to length().

Examples:

[].combinations() = [[]]

[1,2,3].combinations() = [
  [],                  // k = 0
  [1], [2], [3],       // k = 1
  [1,2], [1,3], [2,3], // k = 2
  [1,2,3]              // k = 3
]

Specified by:

combinations in interface Seq<T>

Returns:

a sequence of sequences representing all combinations of this sequence's elements

combinations

IndexedSeq<? extends IndexedSeq<T>> combinations(int k)

Description copied from interface: Seq

Returns all subsets of this sequence containing exactly k distinct elements, i.e., the k-combinations of this sequence.

Specified by:

combinations in interface Seq<T>

Parameters:

k - the size of each subset

Returns:

a sequence of sequences representing all k-element combinations

See Also:

• Combination

crossProduct

Iterator<? extends IndexedSeq<T>> crossProduct(int power)

Description copied from interface: Seq

Returns the n-ary Cartesian power (cross product) of this sequence. Each element of the resulting iterator is a sequence of length power, containing all possible combinations of elements from this sequence.

Example for power = 2:

// Result: [(A,A), (A,B), (A,C), ..., (B,A), (B,B), ..., (Z,Y), (Z,Z)]
CharSeq.rangeClosed('A', 'Z').crossProduct(2);

If power is negative, the result is an empty iterator:

// Result: ()
CharSeq.rangeClosed('A', 'Z').crossProduct(-1);

Specified by:

crossProduct in interface Seq<T>

Parameters:

power - the number of Cartesian multiplications

Returns:

an Iterator over sequences representing the Cartesian power of this sequence

distinct

IndexedSeq<T> distinct()

Description copied from interface: Traversable

Returns a new Traversable containing the elements of this instance with all duplicates removed. Element equality is determined using equals.

Specified by:

distinct in interface Seq<T>

Specified by:

distinct in interface Traversable<T>

Returns:

a new Traversable without duplicate elements

distinctBy

IndexedSeq<T> distinctBy(@NonNull Comparator<? super T> comparator)

Description copied from interface: Traversable

Returns a new Traversable containing the elements of this instance without duplicates, as determined by the given comparator.

Specified by:

distinctBy in interface Seq<T>

Specified by:

distinctBy in interface Traversable<T>

Parameters:

comparator - a comparator used to determine equality of elements

Returns:

a new Traversable with duplicates removed

distinctBy

<U> IndexedSeq<T> distinctBy(@NonNull Function<? super T, ? extends U> keyExtractor)

Description copied from interface: Traversable

Returns a new Traversable containing the elements of this instance without duplicates, based on keys extracted from elements using keyExtractor.

The first occurrence of each key is retained in the resulting sequence.

Specified by:

distinctBy in interface Seq<T>

Specified by:

distinctBy in interface Traversable<T>

Type Parameters:

U - the type of key

Parameters:

keyExtractor - a function to extract keys for determining uniqueness

Returns:

a new Traversable with duplicates removed based on keys

distinctByKeepLast

IndexedSeq<T> distinctByKeepLast(@NonNull Comparator<? super T> comparator)

Description copied from interface: Seq

Returns a sequence with duplicate elements removed, as determined by the provided comparator. When duplicates are found, the **last occurrence** of each element is retained.

Specified by:

distinctByKeepLast in interface Seq<T>

Parameters:

comparator - a comparator defining equality between elements

Returns:

a new sequence with duplicates removed, keeping the last occurrence of each element

distinctByKeepLast

<U> IndexedSeq<T> distinctByKeepLast(@NonNull Function<? super T, ? extends U> keyExtractor)

Description copied from interface: Seq

Returns a sequence with duplicates removed based on a key extracted from each element. The key is obtained via the provided keyExtractor function. When duplicates are found, the **last occurrence** of each element for a given key is retained.

Specified by:

distinctByKeepLast in interface Seq<T>

Type Parameters:

U - the type of the key used for determining uniqueness

Parameters:

keyExtractor - a function extracting a key from each element for uniqueness comparison

Returns:

a new sequence of elements distinct by the extracted key, keeping the last occurrence

drop

IndexedSeq<T> drop(int n)

Description copied from interface: Traversable

Returns a new Traversable without the first n elements, or an empty instance if this contains fewer than n elements.

Specified by:

drop in interface Seq<T>

Specified by:

drop in interface Traversable<T>

Parameters:

n - the number of elements to drop

Returns:

a new instance excluding the first n elements

dropUntil

IndexedSeq<T> dropUntil(@NonNull Predicate<? super T> predicate)

Description copied from interface: Traversable

Returns a new Traversable starting from the first element that satisfies the given predicate, dropping all preceding elements.

Specified by:

dropUntil in interface Seq<T>

Specified by:

dropUntil in interface Traversable<T>

Parameters:

predicate - a condition tested on each element

Returns:

a new instance starting from the first element matching the predicate

dropWhile

IndexedSeq<T> dropWhile(@NonNull Predicate<? super T> predicate)

Description copied from interface: Traversable

Returns a new Traversable starting from the first element that does not satisfy the given predicate, dropping all preceding elements.

This is equivalent to dropUntil(predicate.negate()), which is useful for method references that cannot be negated directly.

Specified by:

dropWhile in interface Seq<T>

Specified by:

dropWhile in interface Traversable<T>

Parameters:

predicate - a condition tested on each element

Returns:

a new instance starting from the first element not matching the predicate

dropRight

IndexedSeq<T> dropRight(int n)

Description copied from interface: Traversable

Returns a new Traversable without the last n elements, or an empty instance if this contains fewer than n elements.

Specified by:

dropRight in interface Seq<T>

Specified by:

dropRight in interface Traversable<T>

Parameters:

n - the number of elements to drop from the end

Returns:

a new instance excluding the last n elements

dropRightUntil

IndexedSeq<T> dropRightUntil(@NonNull Predicate<? super T> predicate)

Description copied from interface: Seq

Drops elements from the end of the sequence until an element satisfies the given predicate. The returned sequence includes the last element that satisfies the predicate.

Specified by:

dropRightUntil in interface Seq<T>

Parameters:

predicate - a condition to test elements, starting from the end

Returns:

a new sequence containing all elements up to and including the last element that satisfies the predicate

dropRightWhile

IndexedSeq<T> dropRightWhile(@NonNull Predicate<? super T> predicate)

Description copied from interface: Seq

Drops elements from the end of the sequence while the given predicate holds.

This is equivalent to dropRightUntil(predicate.negate()). Useful when using method references that cannot be negated directly.

Specified by:

dropRightWhile in interface Seq<T>

Parameters:

predicate - a condition to test elements, starting from the end

Returns:

a new sequence containing all elements up to and including the last element that does not satisfy the predicate

endsWith

default boolean endsWith(@NonNull Seq<? extends T> that)

Description copied from interface: Seq

Checks whether this sequence ends with the given sequence.

Note: If both this sequence and that are infinite, this method may not terminate.

Specified by:

endsWith in interface Seq<T>

Parameters:

that - the sequence to check as a suffix; must not be null

Returns:

true if this sequence ends with that, false otherwise

filter

IndexedSeq<T> filter(@NonNull Predicate<? super T> predicate)

Description copied from interface: Traversable

Returns a new traversable containing only the elements that satisfy the given predicate.

Specified by:

filter in interface Seq<T>

Specified by:

filter in interface Traversable<T>

Parameters:

predicate - the condition to test elements

Returns:

a traversable with elements matching the predicate

reject

IndexedSeq<T> reject(@NonNull Predicate<? super T> predicate)

Description copied from interface: Traversable

Returns a new traversable containing only the elements that do not satisfy the given predicate.

This is equivalent to filter(predicate.negate()).

Specified by:

reject in interface Seq<T>

Specified by:

reject in interface Traversable<T>

Parameters:

predicate - the condition to test elements

Returns:

a traversable with elements not matching the predicate

flatMap

<U> IndexedSeq<U> flatMap(@NonNull Function<? super T, ? extends Iterable<? extends U>> mapper)

Description copied from interface: Traversable

Transforms each element of this Traversable into an Iterable of elements and flattens the resulting iterables into a single Traversable.

Specified by:

flatMap in interface Seq<T>

Specified by:

flatMap in interface Traversable<T>

Type Parameters:

U - the type of elements in the resulting Traversable

Parameters:

mapper - a function mapping elements to iterables

Returns:

a new Traversable containing all elements produced by applying mapper and flattening

groupBy

<C> Map<C, ? extends IndexedSeq<T>> groupBy(@NonNull Function<? super T, ? extends C> classifier)

Description copied from interface: Traversable

Groups elements of this Traversable based on a classifier function.

Specified by:

groupBy in interface Seq<T>

Specified by:

groupBy in interface Traversable<T>

Type Parameters:

C - The type of the group keys

Parameters:

classifier - A function that assigns each element to a group

Returns:

A map where each key corresponds to a group of elements

See Also:

• Traversable.arrangeBy(Function)

indexWhere

default int indexWhere(@NonNull Predicate<? super T> predicate,
 int from)

Description copied from interface: Seq

Returns the index of the first element at or after the specified start index that satisfies the given predicate, or -1 if no such element exists.

Specified by:

indexWhere in interface Seq<T>

Parameters:

predicate - the predicate used to test elements; must not be null

from - the starting index for the search

Returns:

the index >= from of the first matching element, or -1 if none exists

grouped

Iterator<? extends IndexedSeq<T>> grouped(int size)

Description copied from interface: Traversable

Splits this Traversable into consecutive blocks of the given size.

Let length be the number of elements in this Traversable:

• If empty, the resulting Iterator is empty.
• If size <= length, the resulting Iterator contains length / size blocks of size size and possibly a final smaller block of size length % size.
• If size > length, the resulting Iterator contains a single block of size length.

Examples:

[].grouped(1) = []
[].grouped(0) throws
[].grouped(-1) throws
[1,2,3,4].grouped(2) = [[1,2],[3,4]]
[1,2,3,4,5].grouped(2) = [[1,2],[3,4],[5]]
[1,2,3,4].grouped(5) = [[1,2,3,4]]

Note: grouped(size) is equivalent to sliding(size, size).

Specified by:

grouped in interface Seq<T>

Specified by:

grouped in interface Traversable<T>

Parameters:

size - the block size; must be positive

Returns:

an Iterator over blocks of elements

indexOfSlice

default int indexOfSlice(@NonNull Iterable<? extends T> that,
 int from)

Description copied from interface: Seq

Returns the first index at or after the specified start index where this sequence contains the given sequence as a contiguous slice, or -1 if no such slice exists.

Note: This method may not terminate for infinite sequences.

Specified by:

indexOfSlice in interface Seq<T>

Parameters:

that - the sequence to search for; must not be null

from - the starting index for the search

Returns:

the starting index of the first matching slice at or after from, or -1 if not found

init

IndexedSeq<T> init()

Description copied from interface: Traversable

Returns all elements of this Traversable except the last one.

This is the dual of Traversable.tail().

Specified by:

init in interface Seq<T>

Specified by:

init in interface Traversable<T>

Returns:

a new instance containing all elements except the last

initOption

Option<? extends IndexedSeq<T>> initOption()

Description copied from interface: Traversable

Returns all elements of this Traversable except the last one, wrapped in an Option.

This is the dual of Traversable.tailOption().

Specified by:

initOption in interface Seq<T>

Specified by:

initOption in interface Traversable<T>

Returns:

Some(traversable) if non-empty, or None if this Traversable is empty

insert

IndexedSeq<T> insert(int index,
 T element)

Description copied from interface: Seq

Returns a new sequence with the given element inserted at the specified index.

Specified by:

insert in interface Seq<T>

Parameters:

index - the position at which to insert the element

element - the element to insert

Returns:

a new Seq with the element inserted

insertAll

IndexedSeq<T> insertAll(int index,
 @NonNull Iterable<? extends T> elements)

Description copied from interface: Seq

Returns a new sequence with the given elements inserted at the specified index.

Specified by:

insertAll in interface Seq<T>

Parameters:

index - the position at which to insert the elements

elements - the elements to insert; must not be null

Returns:

a new Seq with the elements inserted

intersperse

IndexedSeq<T> intersperse(T element)

Description copied from interface: Seq

Returns a new sequence where the given element is inserted between all elements of this sequence.

Specified by:

intersperse in interface Seq<T>

Parameters:

element - the element to intersperse

Returns:

a new Seq with the element interspersed

isDefinedAt

@Deprecated
default boolean isDefinedAt(Integer index)

Deprecated.

Description copied from interface: PartialFunction

Tests whether a value is contained in the function's domain.

Specified by:

isDefinedAt in interface PartialFunction<Integer,T>

Parameters:

index - a potential input to the function

Returns:

true if the given value is contained in the function's domain, false otherwise

last

default T last()

Description copied from interface: Traversable

Returns the last element of this Traversable.

Specified by:

last in interface Traversable<T>

Returns:

the last element

lastIndexOfSlice

default int lastIndexOfSlice(@NonNull Iterable<? extends T> that,
 int end)

Description copied from interface: Seq

Returns the last index at or before the specified end index where this sequence contains the given sequence as a contiguous slice, or -1 if no such slice exists.

Specified by:

lastIndexOfSlice in interface Seq<T>

Parameters:

that - the sequence to search for; must not be null

end - the maximum index to consider

Returns:

the last index <= end where the slice starts, or -1 if not found

lastIndexWhere

default int lastIndexWhere(@NonNull Predicate<? super T> predicate,
 int end)

Description copied from interface: Seq

Returns the index of the last element at or before the specified end index that satisfies the given predicate, or -1 if no such element exists.

Specified by:

lastIndexWhere in interface Seq<T>

Parameters:

predicate - the predicate used to test elements; must not be null

end - the maximum index to consider

Returns:

the index <= end of the last matching element, or -1 if none exists

map

<U> IndexedSeq<U> map(@NonNull Function<? super T, ? extends U> mapper)

Description copied from interface: Traversable

Transforms the elements of this Traversable to a new type, preserving order if defined.

Specified by:

map in interface Seq<T>

Specified by:

map in interface Traversable<T>

Specified by:

map in interface Value<T>

Type Parameters:

U - the target element type

Parameters:

mapper - a mapping function

Returns:

a new Traversable containing the mapped elements

mapTo

default <U> IndexedSeq<U> mapTo(U value)

Description copied from interface: Value

Maps the underlying value to another fixed value.

Specified by:

mapTo in interface Seq<T>

Specified by:

mapTo in interface Traversable<T>

Specified by:

mapTo in interface Value<T>

Type Parameters:

U - The new component type

Parameters:

value - value to replace the contents with

Returns:

A new value

mapToVoid

default IndexedSeq<Void> mapToVoid()

Description copied from interface: Value

Maps the underlying value to Void

Specified by:

mapToVoid in interface Seq<T>

Specified by:

mapToVoid in interface Traversable<T>

Specified by:

mapToVoid in interface Value<T>

Returns:

A new value of type Void

orElse

IndexedSeq<T> orElse(Iterable<? extends T> other)

Description copied from interface: Traversable

Returns this Traversable if it is non-empty; otherwise, returns the given alternative.

Specified by:

orElse in interface Seq<T>

Specified by:

orElse in interface Traversable<T>

Parameters:

other - an alternative Traversable to return if this is empty

Returns:

this Traversable if non-empty, otherwise other

orElse

IndexedSeq<T> orElse(@NonNull Supplier<? extends Iterable<? extends T>> supplier)

Description copied from interface: Traversable

Returns this Traversable if it is non-empty; otherwise, returns the result of evaluating the given supplier.

Specified by:

orElse in interface Seq<T>

Specified by:

orElse in interface Traversable<T>

Parameters:

supplier - a supplier of an alternative Traversable if this is empty

Returns:

this Traversable if non-empty, otherwise the result of supplier.get()

padTo

IndexedSeq<T> padTo(int length,
 T element)

Description copied from interface: Seq

Returns a new sequence with this sequence padded on the right with the given element until the specified target length is reached.

Note: Lazily-evaluated sequences may need to process all elements to determine the overall length.

Specified by:

padTo in interface Seq<T>

Parameters:

length - the target length of the resulting sequence

element - the element to append as padding

Returns:

a new Seq consisting of this sequence followed by the minimal number of occurrences of element to reach at least length

patch

IndexedSeq<T> patch(int from,
 @NonNull Iterable<? extends T> that,
 int replaced)

Description copied from interface: Seq

Returns a new sequence in which a slice of elements in this sequence is replaced by the elements of another sequence.

Specified by:

patch in interface Seq<T>

Parameters:

from - the starting index of the slice to be replaced

that - the sequence of elements to insert; must not be null

replaced - the number of elements to remove from this sequence starting at from

Returns:

a new Seq with the specified slice replaced

partition

Tuple2<? extends IndexedSeq<T>, ? extends IndexedSeq<T>> partition(@NonNull Predicate<? super T> predicate)

Description copied from interface: Traversable

Splits this Traversable into two partitions according to a predicate.

The first partition contains all elements that satisfy the predicate, and the second contains all elements that do not. The original iteration order is preserved.

Specified by:

partition in interface Seq<T>

Specified by:

partition in interface Traversable<T>

Parameters:

predicate - a predicate used to classify elements

Returns:

a Tuple2 containing the two resulting Traversable instances

peek

IndexedSeq<T> peek(@NonNull Consumer<? super T> action)

Description copied from interface: Value

Performs the given action on the first element if this is an eager implementation. Performs the given action on all elements (the first immediately, successive deferred), if this is a lazy implementation.

Specified by:

peek in interface Seq<T>

Specified by:

peek in interface Traversable<T>

Specified by:

peek in interface Value<T>

Parameters:

action - The action that will be performed on the element(s).

Returns:

this instance

permutations

IndexedSeq<? extends IndexedSeq<T>> permutations()

Description copied from interface: Seq

Returns all unique permutations of this sequence.

Example:

[].permutations() = []

[1, 2, 3].permutations() = [
  [1, 2, 3],
  [1, 3, 2],
  [2, 1, 3],
  [2, 3, 1],
  [3, 1, 2],
  [3, 2, 1]
]

Specified by:

permutations in interface Seq<T>

Returns:

a sequence of all unique permutations of this sequence

prepend

IndexedSeq<T> prepend(T element)

Description copied from interface: Seq

Returns a new sequence with the given element prepended to this sequence.

Specified by:

prepend in interface Seq<T>

Parameters:

element - the element to prepend

Returns:

a new Seq with the element added at the front

prependAll

IndexedSeq<T> prependAll(@NonNull Iterable<? extends T> elements)

Description copied from interface: Seq

Returns a new sequence with all given elements prepended to this sequence.

Specified by:

prependAll in interface Seq<T>

Parameters:

elements - the elements to prepend; must not be null

Returns:

a new Seq with the elements added at the front

remove

IndexedSeq<T> remove(T element)

Description copied from interface: Seq

Returns a new sequence with the first occurrence of the given element removed.

Specified by:

remove in interface Seq<T>

Parameters:

element - the element to remove

Returns:

a new Seq without the first occurrence of the element

removeFirst

IndexedSeq<T> removeFirst(@NonNull Predicate<T> predicate)

Description copied from interface: Seq

Returns a new sequence with the first element that satisfies the given predicate removed.

Specified by:

removeFirst in interface Seq<T>

Parameters:

predicate - the predicate used to identify the element to remove; must not be null

Returns:

a new Seq without the first matching element

removeLast

IndexedSeq<T> removeLast(@NonNull Predicate<T> predicate)

Description copied from interface: Seq

Returns a new sequence with the last element that satisfies the given predicate removed.

Specified by:

removeLast in interface Seq<T>

Parameters:

predicate - the predicate used to identify the element to remove; must not be null

Returns:

a new Seq without the last matching element

removeAt

IndexedSeq<T> removeAt(int index)

Description copied from interface: Seq

Returns a new sequence with the element at the specified position removed. Subsequent elements are shifted to the left (indices decreased by one).

Specified by:

removeAt in interface Seq<T>

Parameters:

index - the position of the element to remove

Returns:

a new Seq without the element at the specified index

removeAll

IndexedSeq<T> removeAll(T element)

Description copied from interface: Seq

Returns a new sequence with all occurrences of the given element removed.

Specified by:

removeAll in interface Seq<T>

Parameters:

element - the element to remove

Returns:

a new Seq without any occurrences of the element

removeAll

IndexedSeq<T> removeAll(@NonNull Iterable<? extends T> elements)

Description copied from interface: Seq

Returns a new sequence with all occurrences of the given elements removed.

Specified by:

removeAll in interface Seq<T>

Parameters:

elements - the elements to remove; must not be null

Returns:

a new Seq without any of the given elements

removeAll

@Deprecated
IndexedSeq<T> removeAll(@NonNull Predicate<? super T> predicate)

Deprecated.

Description copied from interface: Seq

Returns a new Seq consisting of all elements which do not satisfy the given predicate.

Specified by:

removeAll in interface Seq<T>

Parameters:

predicate - the predicate used to test elements

Returns:

a new Seq

replace

IndexedSeq<T> replace(T currentElement,
 T newElement)

Description copied from interface: Traversable

Replaces the first occurrence of currentElement with newElement, if it exists.

Specified by:

replace in interface Seq<T>

Specified by:

replace in interface Traversable<T>

Parameters:

currentElement - the element to be replaced

newElement - the replacement element

Returns:

a new Traversable with the first occurrence of currentElement replaced by newElement

replaceAll

IndexedSeq<T> replaceAll(T currentElement,
 T newElement)

Description copied from interface: Traversable

Replaces all occurrences of currentElement with newElement.

Specified by:

replaceAll in interface Seq<T>

Specified by:

replaceAll in interface Traversable<T>

Parameters:

currentElement - the element to be replaced

newElement - the replacement element

Returns:

a new Traversable with all occurrences of currentElement replaced by newElement

retainAll

IndexedSeq<T> retainAll(@NonNull Iterable<? extends T> elements)

Description copied from interface: Traversable

Retains only the elements from this Traversable that are contained in the given elements.

Specified by:

retainAll in interface Seq<T>

Specified by:

retainAll in interface Traversable<T>

Parameters:

elements - the elements to keep

Returns:

a new Traversable containing only the elements present in elements, in their original order

reverse

IndexedSeq<T> reverse()

Description copied from interface: Seq

Returns a new sequence with the order of elements reversed.

Specified by:

reverse in interface Seq<T>

Returns:

a new Seq with elements in reversed order

reverseIterator

default Iterator<T> reverseIterator()

Description copied from interface: Seq

Returns an iterator that yields elements of this sequence in reversed order.

Note: xs.reverseIterator() is equivalent to xs.reverse().iterator() but may be more efficient.

Specified by:

reverseIterator in interface Seq<T>

Returns:

an Iterator over the elements in reversed order

rotateLeft

IndexedSeq<T> rotateLeft(int n)

Description copied from interface: Seq

Returns a new sequence with the elements circularly rotated to the left by the specified distance.

Example:

// Result: List(3, 4, 5, 1, 2)
List.of(1, 2, 3, 4, 5).rotateLeft(2);

Specified by:

rotateLeft in interface Seq<T>

Parameters:

n - the number of positions to rotate left

Returns:

a new Seq with elements rotated left

rotateRight

IndexedSeq<T> rotateRight(int n)

Description copied from interface: Seq

Returns a new sequence with the elements circularly rotated to the right by the specified distance.

Example:

// Result: List(4, 5, 1, 2, 3)
List.of(1, 2, 3, 4, 5).rotateRight(2);

Specified by:

rotateRight in interface Seq<T>

Parameters:

n - the number of positions to rotate right

Returns:

a new Seq with elements rotated right

scan

IndexedSeq<T> scan(T zero,
 @NonNull BiFunction<? super T, ? super T, ? extends T> operation)

Description copied from interface: Traversable

Computes a prefix scan of the elements of this Traversable.

The neutral element zero may be applied more than once.

Specified by:

scan in interface Seq<T>

Specified by:

scan in interface Traversable<T>

Parameters:

zero - the neutral element for the operator

operation - an associative binary operator

Returns:

a new Traversable containing the prefix scan of the elements

scanLeft

<U> IndexedSeq<U> scanLeft(U zero,
 @NonNull BiFunction<? super U, ? super T, ? extends U> operation)

Description copied from interface: Traversable

Produces a collection containing cumulative results of applying the operator from left to right.

Will not terminate for infinite collections. The results may vary across runs unless the collection is ordered.

Specified by:

scanLeft in interface Seq<T>

Specified by:

scanLeft in interface Traversable<T>

Type Parameters:

U - the type of the resulting elements

Parameters:

zero - the initial value

operation - a binary operator applied to the intermediate result and each element

Returns:

a new Traversable containing the cumulative results

scanRight

<U> IndexedSeq<U> scanRight(U zero,
 @NonNull BiFunction<? super T, ? super U, ? extends U> operation)

Description copied from interface: Traversable

Produces a collection containing cumulative results of applying the operator from right to left.

The head of the resulting collection is the last cumulative result. Will not terminate for infinite collections. Results may vary across runs unless the collection is ordered.

Specified by:

scanRight in interface Seq<T>

Specified by:

scanRight in interface Traversable<T>

Type Parameters:

U - the type of the resulting elements

Parameters:

zero - the initial value

operation - a binary operator applied to each element and the intermediate result

Returns:

a new Traversable containing the cumulative results

segmentLength

default int segmentLength(@NonNull Predicate<? super T> predicate,
 int from)

Description copied from interface: Seq

Returns the length of the longest contiguous segment, starting from the specified index, in which all elements satisfy the given predicate.

Note: This method may not terminate for infinite sequences.

Specified by:

segmentLength in interface Seq<T>

Parameters:

predicate - the predicate used to test elements; must not be null

from - the index at which to start the search

Returns:

the length of the longest segment starting at from where every element satisfies predicate

shuffle

IndexedSeq<T> shuffle()

Description copied from interface: Seq

Returns a new sequence with the elements randomly shuffled.

Specified by:

shuffle in interface Seq<T>

Returns:

a new Seq containing the same elements in a random order

slice

IndexedSeq<T> slice(int beginIndex,
 int endIndex)

Description copied from interface: Seq

Returns a subsequence (slice) of this sequence, starting at beginIndex (inclusive) and ending at endIndex (exclusive).

Examples:

List.of(1, 2, 3, 4).slice(1, 3); // = (2, 3)
List.of(1, 2, 3, 4).slice(0, 4); // = (1, 2, 3, 4)
List.of(1, 2, 3, 4).slice(2, 2); // = ()
List.of(1, 2).slice(1, 0);       // = ()
List.of(1, 2).slice(-10, 10);    // = (1, 2)

See also Seq.subSequence(int, int), which may throw an exception instead of returning a sequence in some cases.

Specified by:

slice in interface Seq<T>

Parameters:

beginIndex - the starting index (inclusive)

endIndex - the ending index (exclusive)

Returns:

a new Seq representing the specified slice

slideBy

Iterator<? extends IndexedSeq<T>> slideBy(@NonNull Function<? super T, ?> classifier)

Description copied from interface: Traversable

Partitions this Traversable into consecutive non-overlapping windows according to a classification function.

Each window contains elements with the same class, as determined by classifier. Two consecutive elements belong to the same window only if classifier returns equal values for both. Otherwise, the current window ends and a new window begins with the next element.

Examples:

[].slideBy(Function.identity()) = []
[1,2,3,4,4,5].slideBy(Function.identity()) = [[1],[2],[3],[4,4],[5]]
[1,2,3,10,12,5,7,20,29].slideBy(x -> x / 10) = [[1,2,3],[10,12],[5,7],[20,29]]

Specified by:

slideBy in interface Seq<T>

Specified by:

slideBy in interface Traversable<T>

Parameters:

classifier - A function classifying elements into groups

Returns:

An Iterator of windows (grouped elements)

sliding

Iterator<? extends IndexedSeq<T>> sliding(int size)

Description copied from interface: Traversable

Slides a window of a given size over this Traversable with a step size of 1.

This is equivalent to calling Traversable.sliding(int, int) with a step size of 1.

Specified by:

sliding in interface Seq<T>

Specified by:

sliding in interface Traversable<T>

Parameters:

size - a positive window size

Returns:

An Iterator of windows, each containing up to size elements

sliding

Iterator<? extends IndexedSeq<T>> sliding(int size,
 int step)

Description copied from interface: Traversable

Slides a window of a specific size with a given step over this Traversable.

Examples:

[].sliding(1, 1) = []
[1,2,3,4,5].sliding(2, 3) = [[1,2],[4,5]]
[1,2,3,4,5].sliding(2, 4) = [[1,2],[5]]
[1,2,3,4,5].sliding(2, 5) = [[1,2]]
[1,2,3,4].sliding(5, 3) = [[1,2,3,4],[4]]

Specified by:

sliding in interface Seq<T>

Specified by:

sliding in interface Traversable<T>

Parameters:

size - a positive window size

step - a positive step size

Returns:

an Iterator of windows with the given size and step

sorted

IndexedSeq<T> sorted()

Description copied from interface: Seq

Returns a new sequence with elements sorted according to their natural order.

Specified by:

sorted in interface Seq<T>

Returns:

a new Seq with elements in natural order

sorted

IndexedSeq<T> sorted(@NonNull Comparator<? super T> comparator)

Description copied from interface: Seq

Returns a new sequence with elements sorted according to the given Comparator.

Specified by:

sorted in interface Seq<T>

Parameters:

comparator - the comparator used to order elements; must not be null

Returns:

a new Seq with elements sorted according to the comparator

sortBy

<U extends Comparable<? super U>> IndexedSeq<T> sortBy(@NonNull Function<? super T, ? extends U> mapper)

Description copied from interface: Seq

Returns a new sequence sorted by comparing elements in a different domain defined by the given mapper.

Specified by:

sortBy in interface Seq<T>

Type Parameters:

U - the type used for comparison

Parameters:

mapper - a function mapping elements to a Comparable domain; must not be null

Returns:

a new Seq sorted according to the mapped values

sortBy

<U> IndexedSeq<T> sortBy(@NonNull Comparator<? super U> comparator,
 Function<? super T, ? extends U> mapper)

Description copied from interface: Seq

Returns a new sequence sorted by comparing elements in a different domain defined by the given mapper, using the provided comparator.

Specified by:

sortBy in interface Seq<T>

Type Parameters:

U - the type used for comparison

Parameters:

comparator - the comparator used to compare mapped values; must not be null

mapper - a function mapping elements to the domain for comparison; must not be null

Returns:

a new Seq sorted according to the mapped values and comparator

span

Tuple2<? extends IndexedSeq<T>, ? extends IndexedSeq<T>> span(@NonNull Predicate<? super T> predicate)

Description copied from interface: Traversable

Splits this Traversable into a prefix and remainder according to the given predicate.

The first element of the returned Tuple is the longest prefix of elements satisfying predicate, and the second element is the remaining elements.

Specified by:

span in interface Seq<T>

Specified by:

span in interface Traversable<T>

Parameters:

predicate - a predicate used to determine the prefix

Returns:

a Tuple containing the prefix and remainder

startsWith

default boolean startsWith(@NonNull Iterable<? extends T> that,
 int offset)

Description copied from interface: Seq

Tests whether this sequence contains the given sequence starting at the specified index.

Note: If both this sequence and the argument sequence are infinite, this method may not terminate.

Specified by:

startsWith in interface Seq<T>

Parameters:

that - the sequence to test; must not be null

offset - the index at which to start checking for the prefix

Returns:

true if that is empty or matches a subsequence of this sequence starting at offset, false otherwise

subSequence

IndexedSeq<T> subSequence(int beginIndex)

Description copied from interface: Seq

Returns a Seq that is a subsequence of this sequence, starting from the specified beginIndex and extending to the end of this sequence.

Examples:

List.of(1, 2).subSequence(0);   // = (1, 2)
List.of(1, 2).subSequence(1);   // = (2)
List.of(1, 2).subSequence(2);   // = ()
List.of(1, 2).subSequence(10);  // throws IndexOutOfBoundsException
List.of(1, 2).subSequence(-10); // throws IndexOutOfBoundsException

See also Seq.drop(int), which provides similar functionality but does not throw an exception for out-of-bounds indices.

Specified by:

subSequence in interface Seq<T>

Parameters:

beginIndex - the starting index (inclusive) of the subsequence

Returns:

a new Seq representing the subsequence from beginIndex to the end

subSequence

IndexedSeq<T> subSequence(int beginIndex,
 int endIndex)

Description copied from interface: Seq

Returns a Seq that is a subsequence of this sequence, starting from the specified beginIndex (inclusive) and ending at endIndex (exclusive).

Examples:

List.of(1, 2, 3, 4).subSequence(1, 3); // = (2, 3)
List.of(1, 2, 3, 4).subSequence(0, 4); // = (1, 2, 3, 4)
List.of(1, 2, 3, 4).subSequence(2, 2); // = ()
List.of(1, 2).subSequence(1, 0);       // throws IndexOutOfBoundsException
List.of(1, 2).subSequence(-10, 1);     // throws IndexOutOfBoundsException
List.of(1, 2).subSequence(0, 10);      // throws IndexOutOfBoundsException

See also Seq.slice(int, int), which returns an empty sequence instead of throwing exceptions when indices are out of range.

Specified by:

subSequence in interface Seq<T>

Parameters:

beginIndex - the starting index (inclusive) of the subsequence

endIndex - the ending index (exclusive) of the subsequence

Returns:

a new Seq representing the subsequence from beginIndex to endIndex - 1

tail

IndexedSeq<T> tail()

Description copied from interface: Traversable

Returns a new Traversable without its first element.

Specified by:

tail in interface Seq<T>

Specified by:

tail in interface Traversable<T>

Returns:

a new Traversable containing all elements except the first

tailOption

Option<? extends IndexedSeq<T>> tailOption()

Description copied from interface: Traversable

Returns a new Traversable without its first element as an Option.

Specified by:

tailOption in interface Seq<T>

Specified by:

tailOption in interface Traversable<T>

Returns:

Some(traversable) if non-empty, otherwise None

take

IndexedSeq<T> take(int n)

Description copied from interface: Traversable

Returns the first n elements of this Traversable, or all elements if n exceeds the length.

Equivalent to sublist(0, max(0, min(length(), n))), but safe for n < 0 or n > length().

If n < 0, an empty instance is returned. If n > length(), the full instance is returned.

Specified by:

take in interface Seq<T>

Specified by:

take in interface Traversable<T>

Parameters:

n - the number of elements to take

Returns:

a new Traversable containing the first n elements

takeUntil

IndexedSeq<T> takeUntil(@NonNull Predicate<? super T> predicate)

Description copied from interface: Traversable

Takes elements from this Traversable until the given predicate holds for an element.

Equivalent to takeWhile(predicate.negate()), but useful when using method references that cannot be negated directly.

Specified by:

takeUntil in interface Seq<T>

Specified by:

takeUntil in interface Traversable<T>

Parameters:

predicate - a condition tested sequentially on the elements

Returns:

a new Traversable containing all elements before the first one that satisfies the predicate

takeWhile

IndexedSeq<T> takeWhile(@NonNull Predicate<? super T> predicate)

Description copied from interface: Traversable

Takes elements from this Traversable while the given predicate holds.

Specified by:

takeWhile in interface Seq<T>

Specified by:

takeWhile in interface Traversable<T>

Parameters:

predicate - a condition tested sequentially on the elements

Returns:

a new Traversable containing all elements up to (but not including) the first one that does not satisfy the predicate

takeRight

IndexedSeq<T> takeRight(int n)

Description copied from interface: Traversable

Returns the last n elements of this Traversable, or all elements if n exceeds the length.

Equivalent to sublist(max(0, length() - n), length()), but safe for n < 0 or n > length().

If n < 0, an empty instance is returned. If n > length(), the full instance is returned.

Specified by:

takeRight in interface Seq<T>

Specified by:

takeRight in interface Traversable<T>

Parameters:

n - the number of elements to take from the end

Returns:

a new Traversable containing the last n elements

takeRightUntil

IndexedSeq<T> takeRightUntil(@NonNull Predicate<? super T> predicate)

Description copied from interface: Seq

Takes elements from the end of the sequence until an element satisfies the given predicate. The returned sequence starts after the last element that satisfies the predicate.

Specified by:

takeRightUntil in interface Seq<T>

Parameters:

predicate - a condition to test elements, starting from the end

Returns:

a new sequence containing all elements after the last element that satisfies the predicate

takeRightWhile

IndexedSeq<T> takeRightWhile(@NonNull Predicate<? super T> predicate)

Description copied from interface: Seq

Takes elements from the end of the sequence while the given predicate holds.

This is an equivalent to takeRightUntil(predicate.negate()). Useful when using method references that cannot be negated directly.

Specified by:

takeRightWhile in interface Seq<T>

Parameters:

predicate - a condition to test elements, starting from the end

Returns:

a new sequence containing all elements after the last element that does not satisfy the predicate

unzip

<T1,T2>
Tuple2<? extends IndexedSeq<T1>, ? extends IndexedSeq<T2>> unzip(@NonNull Function<? super T, Tuple2<? extends T1, ? extends T2>> unzipper)

Description copied from interface: Traversable

Unzips the elements of this Traversable by mapping each element to a pair and splitting them into two separate Traversable collections.

Specified by:

unzip in interface Seq<T>

Specified by:

unzip in interface Traversable<T>

Type Parameters:

T1 - type of the first element in the resulting pairs

T2 - type of the second element in the resulting pairs

Parameters:

unzipper - a function that maps elements of this Traversable to pairs

Returns:

a Tuple2 containing two Traversable collections with the split elements

unzip3

<T1,T2,T3>
Tuple3<? extends IndexedSeq<T1>, ? extends IndexedSeq<T2>, ? extends IndexedSeq<T3>> unzip3(@NonNull Function<? super T, Tuple3<? extends T1, ? extends T2, ? extends T3>> unzipper)

Description copied from interface: Traversable

Unzips the elements of this Traversable by mapping each element to a triple and splitting them into three separate Traversable collections.

Specified by:

unzip3 in interface Seq<T>

Specified by:

unzip3 in interface Traversable<T>

Type Parameters:

T1 - type of the first element in the resulting triples

T2 - type of the second element in the resulting triples

T3 - type of the third element in the resulting triples

Parameters:

unzipper - a function that maps elements of this Traversable to triples

Returns:

a Tuple3 containing three Traversable collections with the split elements

update

IndexedSeq<T> update(int index,
 T element)

Description copied from interface: Seq

Returns a new Seq with the element at the specified index replaced by the given value.

Specified by:

update in interface Seq<T>

Parameters:

index - the index of the element to update

element - the new element to set at the specified index

Returns:

a new Seq with the updated element

update

IndexedSeq<T> update(int index,
 @NonNull Function<? super T, ? extends T> updater)

Description copied from interface: Seq

Returns a new Seq with the element at the specified index updated using the given function.

Specified by:

update in interface Seq<T>

Parameters:

index - the index of the element to update

updater - a function that computes the new element from the existing element

Returns:

a new Seq with the element at index transformed by updater

zip

<U> IndexedSeq<Tuple2<T,U>> zip(@NonNull Iterable<? extends U> that)

Description copied from interface: Traversable

Returns a Traversable formed by pairing elements of this Traversable with elements of another Iterable. Pairing stops when either collection runs out of elements; any remaining elements in the longer collection are ignored.

The length of the resulting Traversable is the minimum of the lengths of this Traversable and that.

Specified by:

zip in interface Seq<T>

Specified by:

zip in interface Traversable<T>

Type Parameters:

U - the type of elements in the second half of each pair

Parameters:

that - an Iterable providing the second element of each pair

Returns:

a new Traversable containing pairs of corresponding elements

zipWith

<U,R> IndexedSeq<R> zipWith(@NonNull Iterable<? extends U> that,
 BiFunction<? super T, ? super U, ? extends R> mapper)

Description copied from interface: Traversable

Returns a Traversable by combining elements of this Traversable with elements of another Iterable using a mapping function. Pairing stops when either collection runs out of elements.

The length of the resulting Traversable is the minimum of the lengths of this Traversable and that.

Specified by:

zipWith in interface Seq<T>

Specified by:

zipWith in interface Traversable<T>

Type Parameters:

U - the type of elements in the second parameter of the mapper

R - the type of elements in the resulting Traversable

Parameters:

that - an Iterable providing the second parameter of the mapper

mapper - a function that combines elements from this and that into a new element

Returns:

a new Traversable containing mapped elements

zipAll

<U> IndexedSeq<Tuple2<T,U>> zipAll(@NonNull Iterable<? extends U> that,
 T thisElem,
 U thatElem)

Description copied from interface: Traversable

Returns a Traversable formed by pairing elements of this Traversable with elements of another Iterable, filling in placeholder elements when one collection is shorter than the other.

The length of the resulting Traversable is the maximum of the lengths of this Traversable and that.

If this Traversable is shorter than that, thisElem is used as a filler. Conversely, if that is shorter, thatElem is used.

Specified by:

zipAll in interface Seq<T>

Specified by:

zipAll in interface Traversable<T>

Type Parameters:

U - the type of elements in the second half of each pair

Parameters:

that - an Iterable providing the second element of each pair

thisElem - the element used to fill missing values if this Traversable is shorter than that

thatElem - the element used to fill missing values if that is shorter than this Traversable

Returns:

a new Traversable containing pairs of elements, including fillers as needed

zipWithIndex

IndexedSeq<Tuple2<T,Integer>> zipWithIndex()

Description copied from interface: Traversable

Zips this Traversable with its indices, starting at 0.

Specified by:

zipWithIndex in interface Seq<T>

Specified by:

zipWithIndex in interface Traversable<T>

Returns:

a new Traversable containing each element paired with its index

zipWithIndex

<U> IndexedSeq<U> zipWithIndex(@NonNull BiFunction<? super T, ? super Integer, ? extends U> mapper)

Description copied from interface: Traversable

Zips this Traversable with its indices and maps the resulting pairs using the provided mapper.

Specified by:

zipWithIndex in interface Seq<T>

Specified by:

zipWithIndex in interface Traversable<T>

Type Parameters:

U - the type of elements in the resulting Traversable

Parameters:

mapper - a function mapping an element and its index to a new element

Returns:

a new Traversable containing the mapped elements

search

default int search(T element)

Searches this sequence for a specific element using a binary search. The sequence must already be sorted into ascending natural order. If it is not sorted, the results are undefined.

Specified by:

search in interface Seq<T>

Parameters:

element - the element to find

Returns:

the index of the search element, if it is contained in the sequence; otherwise, (-(insertion point) - 1). The insertion point is defined as the point at which the element would be inserted into the sequence. Note that this guarantees that the return value will be >= 0 if and only if the element is found.

Throws:

ClassCastException - if T cannot be cast to Comparable<? super T>

search

default int search(T element,
 @NonNull Comparator<? super T> comparator)

Searches this sequence for a specific element using a binary search. The sequence must already be sorted into ascending order according to the specified comparator. If it is not sorted, the results are undefined.

Specified by:

search in interface Seq<T>

Parameters:

element - the element to find

comparator - the comparator by which this sequence is ordered

Returns:

the index of the search element, if it is contained in the sequence; otherwise, (-(insertion point) - 1). The insertion point is defined as the point at which the element would be inserted into the sequence. Note that this guarantees that the return value will be >= 0 if and only if the element is found.