T - component type of this Streampublic interface Stream<T> extends LinearSeq<T>
Stream is lazy sequence of elements which may be infinitely long.
Its immutability makes it suitable for concurrent programming.
A Stream is composed of a head element and a lazy evaluated tail Stream.
There are two implementations of the Stream interface:
Stream.Empty, which represents the empty Stream.Stream.Cons, which represents a Stream containing one or more elements.Stream:
// factory methods
Stream.empty() // = Stream.of() = Nil.instance()
Stream.of(x) // = new Cons<>(x, Nil.instance())
Stream.of(Object...) // e.g. Stream.of(1, 2, 3)
Stream.ofAll(Iterable) // e.g. Stream.ofAll(List.of(1, 2, 3)) = 1, 2, 3
Stream.ofAll(<primitive array>) // e.g. List.ofAll(1, 2, 3) = 1, 2, 3
// int sequences
Stream.from(0) // = 0, 1, 2, 3, ...
Stream.range(0, 3) // = 0, 1, 2
Stream.rangeClosed(0, 3) // = 0, 1, 2, 3
// generators
Stream.cons(Object, Supplier) // e.g. Stream.cons(current, () -> next(current));
Stream.continually(Supplier) // e.g. Stream.continually(Math::random);
Stream.iterate(Object, Function)// e.g. Stream.iterate(1, i -> i * 2);
Factory method applications:
Stream<Integer> s1 = Stream.of(1);
Stream<Integer> s2 = Stream.of(1, 2, 3);
// = Stream.of(new Integer[] {1, 2, 3});
Stream<int[]> s3 = Stream.ofAll(1, 2, 3);
Stream<List<Integer>> s4 = Stream.ofAll(List.of(1, 2, 3));
Stream<Integer> s5 = Stream.ofAll(1, 2, 3);
Stream<Integer> s6 = Stream.ofAll(List.of(1, 2, 3));
// cuckoo's egg
Stream<Integer[]> s7 = Stream.<Integer[]> of(new Integer[] {1, 2, 3});
Example: Generating prime numbers
// = Stream(2L, 3L, 5L, 7L, ...)
Stream.iterate(2L, PrimeNumbers::nextPrimeFrom)
// helpers
static long nextPrimeFrom(long num) {
return Stream.from(num + 1).find(PrimeNumbers::isPrime).get();
}
static boolean isPrime(long num) {
return !Stream.rangeClosed(2L, (long) Math.sqrt(num)).exists(d -> num % d == 0);
}
See Okasaki, Chris: Purely Functional Data Structures (p. 34 ff.). Cambridge, 2003.| Modifier and Type | Interface and Description |
|---|---|
static class |
Stream.Cons<T>
Non-empty
Stream, consisting of a head, and tail. |
static class |
Stream.Empty<T>
The empty Stream.
|
| Modifier and Type | Field and Description |
|---|---|
static long |
serialVersionUID |
| Modifier and Type | Method and Description |
|---|---|
default Stream<T> |
append(T element)
Appends an element to this.
|
default Stream<T> |
appendAll(Iterable<? extends T> elements)
Appends all given elements to this.
|
default Stream<T> |
appendSelf(Function<? super Stream<T>,? extends Stream<T>> mapper)
Appends itself to the end of stream with
mapper function. |
default List<T> |
asJava()
Creates an immutable
List view on top of this Seq,
i.e. |
default Stream<T> |
asJava(Consumer<? super List<T>> action)
|
default List<T> |
asJavaMutable()
Creates a mutable
List view on top of this Seq,
i.e. |
default Stream<T> |
asJavaMutable(Consumer<? super List<T>> action)
|
default <R> Stream<R> |
collect(PartialFunction<? super T,? extends R> partialFunction)
Collects all elements that are in the domain of the given
partialFunction by mapping the elements to type R. |
static <T> Collector<T,ArrayList<T>,Stream<T>> |
collector()
Returns a
Collector which may be used in conjunction with
Stream.collect(java.util.stream.Collector) to obtain a Stream. |
default Stream<Stream<T>> |
combinations()
Returns the union of all combinations from k = 0 to length().
|
default Stream<Stream<T>> |
combinations(int k)
Returns the k-combination of this traversable, i.e.
|
static <T> Stream<T> |
concat(Iterable<? extends Iterable<? extends T>> iterables)
Lazily creates a Stream in O(1) which traverses along the concatenation of the given iterables.
|
static <T> Stream<T> |
concat(Iterable<? extends T>... iterables)
Lazily creates a Stream in O(1) which traverses along the concatenation of the given iterables.
|
static <T> Stream<T> |
cons(T head,
Supplier<? extends Stream<? extends T>> tailSupplier)
Constructs a Stream of a head element and a tail supplier.
|
static <T> Stream<T> |
continually(Supplier<? extends T> supplier)
Generates an (theoretically) infinitely long Stream using a value Supplier.
|
static <T> Stream<T> |
continually(T t)
Repeats an element infinitely often.
|
default Iterator<Stream<T>> |
crossProduct(int power)
Calculates the n-ary cartesian power (or cross product or simply product) of this.
|
default Stream<T> |
cycle()
Repeat the elements of this Stream infinitely.
|
default Stream<T> |
cycle(int count)
Repeat the elements of this Stream
count times. |
default Stream<T> |
distinct()
Returns a new version of this which contains no duplicates.
|
default Stream<T> |
distinctBy(Comparator<? super T> comparator)
Returns a new version of this which contains no duplicates.
|
default <U> Stream<T> |
distinctBy(Function<? super T,? extends U> keyExtractor)
Returns a new version of this which contains no duplicates.
|
default Stream<T> |
drop(int n)
Drops the first n elements of this or all elements, if this length < n.
|
default Stream<T> |
dropRight(int n)
Drops the last n elements of this or all elements, if this length < n.
|
default Stream<T> |
dropRightUntil(Predicate<? super T> predicate)
Drops elements until the predicate holds for the current element, starting from the end.
|
default Stream<T> |
dropRightWhile(Predicate<? super T> predicate)
Drops elements while the predicate holds for the current element, starting from the end.
|
default Stream<T> |
dropUntil(Predicate<? super T> predicate)
Drops elements until the predicate holds for the current element.
|
default Stream<T> |
dropWhile(Predicate<? super T> predicate)
Drops elements while the predicate holds for the current element.
|
static <T> Stream<T> |
empty()
Returns the single instance of Nil.
|
default Stream<T> |
extend(Function<? super T,? extends T> nextFunction)
Extends (continues) this
Stream with a Stream of values created by applying
consecutively provided Function to the last element of the original Stream. |
default Stream<T> |
extend(Supplier<? extends T> nextSupplier)
Extends (continues) this
Stream with values provided by a Supplier |
default Stream<T> |
extend(T next)
Extends (continues) this
Stream with a constantly repeated value. |
static <T> Stream<T> |
fill(int n,
Supplier<? extends T> s)
Returns a Stream containing
n values supplied by a given Supplier s. |
static <T> Stream<T> |
fill(int n,
T element)
Returns a Stream containing
n times the given element |
default Stream<T> |
filter(Predicate<? super T> predicate)
Returns a new traversable consisting of all elements which satisfy the given predicate.
|
default <U> Stream<U> |
flatMap(Function<? super T,? extends Iterable<? extends U>> mapper)
FlatMaps this Traversable.
|
static Stream<Integer> |
from(int value)
Returns an infinitely long Stream of
int values starting from from. |
static Stream<Integer> |
from(int value,
int step)
Returns an infinite long Stream of
int values starting from value and spaced by step. |
static Stream<Long> |
from(long value)
Returns an infinitely long Stream of
long values starting from from. |
static Stream<Long> |
from(long value,
long step)
Returns an infinite long Stream of
long values starting from value and spaced by step. |
default T |
get(int index)
Returns the element at the specified index.
|
default <C> Map<C,Stream<T>> |
groupBy(Function<? super T,? extends C> classifier)
Groups this elements by classifying the elements.
|
default Iterator<Stream<T>> |
grouped(int size)
Groups this
Traversable into fixed size blocks. |
default boolean |
hasDefiniteSize()
Checks if this Traversable is known to have a finite size.
|
default int |
indexOf(T element,
int from)
Returns the index of the first occurrence of the given element after or at some start index
or -1 if this does not contain the given element.
|
default Stream<T> |
init()
Dual of Traversable.tail(), returning all elements except the last.
|
default Option<Stream<T>> |
initOption()
Dual of Traversable.tailOption(), returning all elements except the last as
Option. |
default Stream<T> |
insert(int index,
T element)
Inserts the given element at the specified index.
|
default Stream<T> |
insertAll(int index,
Iterable<? extends T> elements)
Inserts the given elements at the specified index.
|
default Stream<T> |
intersperse(T element)
Inserts an element between all elements of this Traversable.
|
default boolean |
isAsync()
A
Stream is computed synchronously. |
default boolean |
isLazy()
A
Stream is computed lazily. |
default boolean |
isTraversableAgain()
Checks if this Traversable can be repeatedly traversed.
|
static <T> Stream<T> |
iterate(Supplier<? extends Option<? extends T>> supplier)
Generates a (theoretically) infinitely long Stream using a repeatedly invoked supplier
that provides a
Some for each next value and a None for the end. |
static <T> Stream<T> |
iterate(T seed,
Function<? super T,? extends T> f)
Generates a (theoretically) infinitely long Stream using a function to calculate the next value
based on the previous.
|
default T |
last()
Dual of Traversable.head(), returning the last element.
|
default int |
lastIndexOf(T element,
int end)
Returns the index of the last occurrence of the given element before or at a given end index
or -1 if this does not contain the given element.
|
default Stream<T> |
leftPadTo(int length,
T element)
A copy of this sequence with an element prepended until a given target length is reached.
|
default int |
length()
Computes the number of elements of this Traversable.
|
default <U> Stream<U> |
map(Function<? super T,? extends U> mapper)
Maps the elements of this
Traversable to elements of a new type preserving their order, if any. |
static <T> Stream<T> |
narrow(Stream<? extends T> stream)
Narrows a widened
Stream<? extends T> to Stream<T>
by performing a type-safe cast. |
static <T> Stream<T> |
of(T... elements)
Creates a Stream of the given elements.
|
static <T> Stream<T> |
of(T element)
Returns a singleton
Stream, i.e. |
static Stream<Boolean> |
ofAll(boolean... elements)
Creates a Stream from boolean values.
|
static Stream<Byte> |
ofAll(byte... elements)
Creates a Stream from byte values.
|
static Stream<Character> |
ofAll(char... elements)
Creates a Stream from char values.
|
static Stream<Double> |
ofAll(double... elements)
Creates a Stream values double values.
|
static Stream<Float> |
ofAll(float... elements)
Creates a Stream from float values.
|
static Stream<Integer> |
ofAll(int... elements)
Creates a Stream from int values.
|
static <T> Stream<T> |
ofAll(Iterable<? extends T> elements)
Creates a Stream of the given elements.
|
static Stream<Long> |
ofAll(long... elements)
Creates a Stream from long values.
|
static Stream<Short> |
ofAll(short... elements)
Creates a Stream from short values.
|
static <T> Stream<T> |
ofAll(Stream<? extends T> javaStream)
Creates a Stream that contains the elements of the given
Stream. |
default Stream<T> |
orElse(Iterable<? extends T> other)
Returns this
Traversable if it is nonempty, otherwise return the alternative. |
default Stream<T> |
orElse(Supplier<? extends Iterable<? extends T>> supplier)
Returns this
Traversable if it is nonempty, otherwise return the result of evaluating supplier. |
default Stream<T> |
padTo(int length,
T element)
A copy of this sequence with an element appended until a given target length is reached.
|
default Tuple2<Stream<T>,Stream<T>> |
partition(Predicate<? super T> predicate)
Creates a partition of this
Traversable by splitting this elements in two in distinct traversables
according to a predicate. |
default Stream<T> |
patch(int from,
Iterable<? extends T> that,
int replaced)
Produces a new list where a slice of elements in this list is replaced by another sequence.
|
default Stream<T> |
peek(Consumer<? super T> action)
Performs the given
action on the first element if this is an eager implementation. |
default Stream<Stream<T>> |
permutations()
Computes all unique permutations.
|
default Stream<T> |
prepend(T element)
Prepends an element to this.
|
default Stream<T> |
prependAll(Iterable<? extends T> elements)
Prepends all given elements to this.
|
static Stream<Character> |
range(char from,
char toExclusive) |
static Stream<Integer> |
range(int from,
int toExclusive)
Creates a Stream of int numbers starting from
from, extending to toExclusive - 1. |
static Stream<Long> |
range(long from,
long toExclusive)
Creates a Stream of long numbers starting from
from, extending to toExclusive - 1. |
static Stream<Character> |
rangeBy(char from,
char toExclusive,
int step) |
static Stream<Double> |
rangeBy(double from,
double toExclusive,
double step) |
static Stream<Integer> |
rangeBy(int from,
int toExclusive,
int step)
Creates a Stream of int numbers starting from
from, extending to toExclusive - 1,
with step. |
static Stream<Long> |
rangeBy(long from,
long toExclusive,
long step)
Creates a Stream of long numbers starting from
from, extending to toExclusive - 1,
with step. |
static Stream<Character> |
rangeClosed(char from,
char toInclusive) |
static Stream<Integer> |
rangeClosed(int from,
int toInclusive)
Creates a Stream of int numbers starting from
from, extending to toInclusive. |
static Stream<Long> |
rangeClosed(long from,
long toInclusive)
Creates a Stream of long numbers starting from
from, extending to toInclusive. |
static Stream<Character> |
rangeClosedBy(char from,
char toInclusive,
int step) |
static Stream<Double> |
rangeClosedBy(double from,
double toInclusive,
double step) |
static Stream<Integer> |
rangeClosedBy(int from,
int toInclusive,
int step)
Creates a Stream of int numbers starting from
from, extending to toInclusive,
with step. |
static Stream<Long> |
rangeClosedBy(long from,
long toInclusive,
long step)
Creates a Stream of long numbers starting from
from, extending to toInclusive,
with step. |
default Stream<T> |
reject(Predicate<? super T> predicate)
Returns a new traversable consisting of all elements which do not satisfy the given predicate.
|
default Stream<T> |
remove(T element)
Removes the first occurrence of the given element.
|
default Stream<T> |
removeAll(Iterable<? extends T> elements)
Removes all occurrences of the given elements.
|
default Stream<T> |
removeAll(Predicate<? super T> predicate)
Deprecated.
|
default Stream<T> |
removeAll(T element)
Removes all occurrences of the given element.
|
default Stream<T> |
removeAt(int index)
Removes the element at the specified position in this sequence.
|
default Stream<T> |
removeFirst(Predicate<T> predicate)
Removes the first occurrence that satisfy predicate
|
default Stream<T> |
removeLast(Predicate<T> predicate)
Removes the last occurrence that satisfy predicate
|
default Stream<T> |
replace(T currentElement,
T newElement)
Replaces the first occurrence (if exists) of the given currentElement with newElement.
|
default Stream<T> |
replaceAll(T currentElement,
T newElement)
Replaces all occurrences of the given currentElement with newElement.
|
default Stream<T> |
retainAll(Iterable<? extends T> elements)
Keeps all occurrences of the given elements from this.
|
default Stream<T> |
reverse()
Reverses the order of elements.
|
default Stream<T> |
rotateLeft(int n)
Circular rotates the elements by the specified distance to the left direction.
|
default Stream<T> |
rotateRight(int n)
Circular rotates the elements by the specified distance to the right direction.
|
default Stream<T> |
scan(T zero,
BiFunction<? super T,? super T,? extends T> operation)
Computes a prefix scan of the elements of the collection.
|
default <U> Stream<U> |
scanLeft(U zero,
BiFunction<? super U,? super T,? extends U> operation)
Produces a collection containing cumulative results of applying the
operator going left to right.
|
default <U> Stream<U> |
scanRight(U zero,
BiFunction<? super T,? super U,? extends U> operation)
Produces a collection containing cumulative results of applying the
operator going right to left.
|
default Stream<T> |
shuffle()
Randomize the order of the elements in the current sequence.
|
default Stream<T> |
slice(int beginIndex,
int endIndex)
Returns a Seq that is a slice of this.
|
default Iterator<Stream<T>> |
slideBy(Function<? super T,?> classifier)
Slides a non-overlapping window of a variable size over this
Traversable. |
default Iterator<Stream<T>> |
sliding(int size)
Slides a window of a specific
size and step size 1 over this Traversable by calling
Traversable.sliding(int, int). |
default Iterator<Stream<T>> |
sliding(int size,
int step)
Slides a window of a specific
size and step size over this Traversable. |
default <U> Stream<T> |
sortBy(Comparator<? super U> comparator,
Function<? super T,? extends U> mapper)
Sorts this elements by comparing the elements in a different domain, using the given
mapper. |
default <U extends Comparable<? super U>> |
sortBy(Function<? super T,? extends U> mapper)
Sorts this elements by comparing the elements in a different domain, using the given
mapper. |
default Stream<T> |
sorted()
Sorts this elements according to their natural order.
|
default Stream<T> |
sorted(Comparator<? super T> comparator)
Sorts this elements according to the provided
Comparator. |
default Tuple2<Stream<T>,Stream<T>> |
span(Predicate<? super T> predicate)
Returns a tuple where the first element is the longest prefix of elements that satisfy the given
predicate and the second element is the remainder. |
default Tuple2<Stream<T>,Stream<T>> |
splitAt(int n)
Splits a Seq at the specified index.
|
default Tuple2<Stream<T>,Stream<T>> |
splitAt(Predicate<? super T> predicate)
Splits a sequence at the first element which satisfies the
Predicate, e.g. |
default Tuple2<Stream<T>,Stream<T>> |
splitAtInclusive(Predicate<? super T> predicate)
Splits a sequence at the first element which satisfies the
Predicate, e.g. |
default String |
stringPrefix()
Returns the name of this Value type, which is used by toString().
|
default Stream<T> |
subSequence(int beginIndex)
Returns a Seq that is a subsequence of this.
|
default Stream<T> |
subSequence(int beginIndex,
int endIndex)
Returns a Seq that is a subsequence of this.
|
static <T> Stream<T> |
tabulate(int n,
Function<? super Integer,? extends T> f)
Returns a Stream containing
n values of a given Function f
over a range of integer values from 0 to n - 1. |
Stream<T> |
tail()
Drops the first element of a non-empty Traversable.
|
default Option<Stream<T>> |
tailOption()
Drops the first element of a non-empty Traversable and returns an
Option. |
default Stream<T> |
take(int n)
Takes the first n elements of this or all elements, if this length < n.
|
default Stream<T> |
takeRight(int n)
Takes the last n elements of this or all elements, if this length < n.
|
default Stream<T> |
takeRightUntil(Predicate<? super T> predicate)
Takes elements until the predicate holds for the current element, starting from the end.
|
default Stream<T> |
takeRightWhile(Predicate<? super T> predicate)
Takes elements while the predicate holds for the current element, starting from the end.
|
default Stream<T> |
takeUntil(Predicate<? super T> predicate)
Takes elements until the predicate holds for the current element.
|
default Stream<T> |
takeWhile(Predicate<? super T> predicate)
Takes elements while the predicate holds for the current element.
|
default <U> U |
transform(Function<? super Stream<T>,? extends U> f)
Transforms this
Stream. |
static <T> Stream<Stream<T>> |
transpose(Stream<Stream<T>> matrix)
Transposes the rows and columns of a
Stream matrix. |
static <T> Stream<T> |
unfold(T seed,
Function<? super T,Option<Tuple2<? extends T,? extends T>>> f)
Creates a Stream from a seed value and a function.
|
static <T,U> Stream<U> |
unfoldLeft(T seed,
Function<? super T,Option<Tuple2<? extends T,? extends U>>> f)
Creates a Stream from a seed value and a function.
|
static <T,U> Stream<U> |
unfoldRight(T seed,
Function<? super T,Option<Tuple2<? extends U,? extends T>>> f)
Creates a Stream from a seed value and a function.
|
default <T1,T2> Tuple2<Stream<T1>,Stream<T2>> |
unzip(Function<? super T,Tuple2<? extends T1,? extends T2>> unzipper)
Unzips this elements by mapping this elements to pairs which are subsequently split into two distinct
sets.
|
default <T1,T2,T3> Tuple3<Stream<T1>,Stream<T2>,Stream<T3>> |
unzip3(Function<? super T,Tuple3<? extends T1,? extends T2,? extends T3>> unzipper)
Unzips this elements by mapping this elements to triples which are subsequently split into three distinct
sets.
|
default Stream<T> |
update(int index,
Function<? super T,? extends T> updater)
Updates the given element at the specified index using the specified function.
|
default Stream<T> |
update(int index,
T element)
Updates the given element at the specified index.
|
default <U> Stream<Tuple2<T,U>> |
zip(Iterable<? extends U> that)
Returns a traversable formed from this traversable and another Iterable collection by combining
corresponding elements in pairs.
|
default <U> Stream<Tuple2<T,U>> |
zipAll(Iterable<? extends U> iterable,
T thisElem,
U thatElem)
Returns a traversable formed from this traversable and another Iterable by combining corresponding elements in
pairs.
|
default <U,R> Stream<R> |
zipWith(Iterable<? extends U> that,
BiFunction<? super T,? super U,? extends R> mapper)
Returns a traversable formed from this traversable and another Iterable collection by mapping elements.
|
default Stream<Tuple2<T,Integer>> |
zipWithIndex()
Zips this traversable with its indices.
|
default <U> Stream<U> |
zipWithIndex(BiFunction<? super T,? super Integer,? extends U> mapper)
Returns a traversable formed from this traversable and another Iterable collection by mapping elements.
|
asPartialFunction, indexOfSlice, indexWhere, isDefinedAt, lastIndexOfSlice, lastIndexWhere, narrow, reverseIterator, search, search, segmentLengthapply, containsSlice, crossProduct, crossProduct, endsWith, foldRight, indexOf, indexOfOption, indexOfOption, indexOfSlice, indexOfSliceOption, indexOfSliceOption, indexWhere, indexWhereOption, indexWhereOption, isSequential, iterator, lastIndexOf, lastIndexOfOption, lastIndexOfOption, lastIndexOfSlice, lastIndexOfSliceOption, lastIndexOfSliceOption, lastIndexWhere, lastIndexWhereOption, lastIndexWhereOption, lift, narrow, prefixLength, startsWith, startsWith, withDefault, withDefaultValuearrangeBy, average, containsAll, count, equals, existsUnique, find, findLast, foldLeft, forEachWithIndex, get, hashCode, head, headOption, isDistinct, isEmpty, isOrdered, isSingleValued, iterator, lastOption, max, maxBy, maxBy, min, minBy, minBy, mkCharSeq, mkCharSeq, mkCharSeq, mkString, mkString, mkString, narrow, nonEmpty, product, reduceLeft, reduceLeftOption, reduceRight, reduceRightOption, single, singleOption, size, spliterator, sumfold, reduce, reduceOptioncollect, collect, contains, corresponds, eq, exists, forAll, forEach, getOrElse, getOrElse, getOrElseThrow, getOrElseTry, getOrNull, narrow, out, out, stderr, stdout, 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, toVectorgetIfDefined, unliftstatic final long serialVersionUID
static <T> Collector<T,ArrayList<T>,Stream<T>> collector()
Collector which may be used in conjunction with
Stream.collect(java.util.stream.Collector) to obtain a Stream.T - Component type of the Stream.@SafeVarargs static <T> Stream<T> concat(Iterable<? extends T>... iterables)
T - Component type.iterables - The iterablesStreamstatic <T> Stream<T> concat(Iterable<? extends Iterable<? extends T>> iterables)
T - Component type.iterables - The iterable of iterablesStreamstatic Stream<Integer> from(int value)
int values starting from from.
The Stream extends to Integer.MIN_VALUE when passing Integer.MAX_VALUE.
value - a start int valuefromstatic Stream<Integer> from(int value, int step)
int values starting from value and spaced by step.
The Stream extends to Integer.MIN_VALUE when passing Integer.MAX_VALUE.
value - a start int valuestep - the step by which to advance on each next valueStream of int values starting from fromstatic Stream<Long> from(long value)
long values starting from from.
The Stream extends to Integer.MIN_VALUE when passing Long.MAX_VALUE.
value - a start long valuefromstatic Stream<Long> from(long value, long step)
long values starting from value and spaced by step.
The Stream extends to Long.MIN_VALUE when passing Long.MAX_VALUE.
value - a start long valuestep - the step by which to advance on each next valueStream of long values starting from fromstatic <T> Stream<T> continually(Supplier<? extends T> supplier)
T - value typesupplier - A Supplier of Stream valuesstatic <T> Stream<T> iterate(T seed, Function<? super T,? extends T> f)
T - value typeseed - The first value in the Streamf - A function to calculate the next value based on the previousstatic <T> Stream<T> iterate(Supplier<? extends Option<? extends T>> supplier)
Some for each next value and a None for the end.
The Supplier will be invoked only that many times until it returns None,
and repeated iteration over the stream will produce the same values in the same order,
without any further invocations to the Supplier.T - value typesupplier - A Supplier of iterator valuesstatic <T> Stream<T> cons(T head, Supplier<? extends Stream<? extends T>> tailSupplier)
T - value typehead - The head element of the StreamtailSupplier - A supplier of the tail values. To end the stream, return empty().static <T> Stream<T> empty()
Nil.instance().
Note: this method intentionally returns type Stream and not Nil. This comes handy when folding.
If you explicitly need type Nil use Stream.Empty.instance().
T - Component type of Nil, determined by type inference in the particular context.static <T> Stream<T> narrow(Stream<? extends T> stream)
Stream<? extends T> to Stream<T>
by performing a type-safe cast. This is eligible because immutable/read-only
collections are covariant.T - Component type of the Stream.stream - A Stream.stream instance as narrowed type Stream<T>.static <T> Stream<T> of(T element)
Stream, i.e. a Stream of one element.@SafeVarargs static <T> Stream<T> of(T... elements)
Stream.of(1, 2, 3, 4)
= Nil.instance().prepend(4).prepend(3).prepend(2).prepend(1)
= new Cons(1, new Cons(2, new Cons(3, new Cons(4, Nil.instance()))))T - Component type of the Stream.elements - Zero or more elements.static <T> Stream<T> tabulate(int n, Function<? super Integer,? extends T> f)
n values of a given Function f
over a range of integer values from 0 to n - 1.T - Component type of the Streamn - The number of elements in the Streamf - The Function computing element valuesf(0),f(1), ..., f(n - 1)NullPointerException - if f is nullstatic <T> Stream<T> fill(int n, Supplier<? extends T> s)
n values supplied by a given Supplier s.T - Component type of the Streamn - The number of elements in the Streams - The Supplier computing element valuesn, where each element contains the result supplied by s.NullPointerException - if s is nullstatic <T> Stream<T> fill(int n, T element)
n times the given elementT - Component type of the Streamn - The number of elements in the Streamelement - The elementn, where each element is the given element.static <T> Stream<T> ofAll(Iterable<? extends T> elements)
T - Component type of the Stream.elements - An Iterable of elements.static <T> Stream<T> ofAll(Stream<? extends T> javaStream)
Stream.T - Component type of the Stream.javaStream - A Streamstatic Stream<Boolean> ofAll(boolean... elements)
elements - boolean valuesNullPointerException - if elements is nullstatic Stream<Byte> ofAll(byte... elements)
elements - byte valuesNullPointerException - if elements is nullstatic Stream<Character> ofAll(char... elements)
elements - char valuesNullPointerException - if elements is nullstatic Stream<Double> ofAll(double... elements)
elements - double valuesNullPointerException - if elements is nullstatic Stream<Float> ofAll(float... elements)
elements - float valuesNullPointerException - if elements is nullstatic Stream<Integer> ofAll(int... elements)
elements - int valuesNullPointerException - if elements is nullstatic Stream<Long> ofAll(long... elements)
elements - long valuesNullPointerException - if elements is nullstatic Stream<Short> ofAll(short... elements)
elements - short valuesNullPointerException - if elements is null@GwtIncompatible static Stream<Double> rangeBy(double from, double toExclusive, double step)
static Stream<Integer> range(int from, int toExclusive)
from, extending to toExclusive - 1.
Examples:
Stream.range(0, 0) // = Stream()
Stream.range(2, 0) // = Stream()
Stream.range(-2, 2) // = Stream(-2, -1, 0, 1)
from - the first numbertoExclusive - the last number + 1Nil if from >= toExclusivestatic Stream<Integer> rangeBy(int from, int toExclusive, int step)
from, extending to toExclusive - 1,
with step.
Examples:
Stream.rangeBy(1, 3, 1) // = Stream(1, 2)
Stream.rangeBy(1, 4, 2) // = Stream(1, 3)
Stream.rangeBy(4, 1, -2) // = Stream(4, 2)
Stream.rangeBy(4, 1, 2) // = Stream()
from - the first numbertoExclusive - the last number + 1step - the stepNil iffrom >= toInclusive and step > 0 orfrom <= toInclusive and step < 0IllegalArgumentException - if step is zerostatic Stream<Long> range(long from, long toExclusive)
from, extending to toExclusive - 1.
Examples:
Stream.range(0L, 0L) // = Stream()
Stream.range(2L, 0L) // = Stream()
Stream.range(-2L, 2L) // = Stream(-2L, -1L, 0L, 1L)
from - the first numbertoExclusive - the last number + 1Nil if from >= toExclusivestatic Stream<Long> rangeBy(long from, long toExclusive, long step)
from, extending to toExclusive - 1,
with step.
Examples:
Stream.rangeBy(1L, 3L, 1L) // = Stream(1L, 2L)
Stream.rangeBy(1L, 4L, 2L) // = Stream(1L, 3L)
Stream.rangeBy(4L, 1L, -2L) // = Stream(4L, 2L)
Stream.rangeBy(4L, 1L, 2L) // = Stream()
from - the first numbertoExclusive - the last number + 1step - the stepNil iffrom >= toInclusive and step > 0 orfrom <= toInclusive and step < 0IllegalArgumentException - if step is zero@GwtIncompatible static Stream<Double> rangeClosedBy(double from, double toInclusive, double step)
static Stream<Integer> rangeClosed(int from, int toInclusive)
from, extending to toInclusive.
Examples:
Stream.rangeClosed(0, 0) // = Stream(0)
Stream.rangeClosed(2, 0) // = Stream()
Stream.rangeClosed(-2, 2) // = Stream(-2, -1, 0, 1, 2)
from - the first numbertoInclusive - the last numberNil if from > toInclusivestatic Stream<Integer> rangeClosedBy(int from, int toInclusive, int step)
from, extending to toInclusive,
with step.
Examples:
Stream.rangeClosedBy(1, 3, 1) // = Stream(1, 2, 3)
Stream.rangeClosedBy(1, 4, 2) // = Stream(1, 3)
Stream.rangeClosedBy(4, 1, -2) // = Stream(4, 2)
Stream.rangeClosedBy(4, 1, 2) // = Stream()
from - the first numbertoInclusive - the last numberstep - the stepNil iffrom > toInclusive and step > 0 orfrom < toInclusive and step < 0IllegalArgumentException - if step is zerostatic Stream<Long> rangeClosed(long from, long toInclusive)
from, extending to toInclusive.
Examples:
Stream.rangeClosed(0L, 0L) // = Stream(0L)
Stream.rangeClosed(2L, 0L) // = Stream()
Stream.rangeClosed(-2L, 2L) // = Stream(-2L, -1L, 0L, 1L, 2L)
from - the first numbertoInclusive - the last numberNil if from > toInclusivestatic Stream<Long> rangeClosedBy(long from, long toInclusive, long step)
from, extending to toInclusive,
with step.
Examples:
Stream.rangeClosedBy(1L, 3L, 1L) // = Stream(1L, 2L, 3L)
Stream.rangeClosedBy(1L, 4L, 2L) // = Stream(1L, 3L)
Stream.rangeClosedBy(4L, 1L, -2L) // = Stream(4L, 2L)
Stream.rangeClosedBy(4L, 1L, 2L) // = Stream()
from - the first numbertoInclusive - the last numberstep - the stepNil iffrom > toInclusive and step > 0 orfrom < toInclusive and step < 0IllegalArgumentException - if step is zerostatic <T> Stream<Stream<T>> transpose(Stream<Stream<T>> matrix)
Stream matrix.T - matrix element typematrix - to be transposed.Stream matrix.IllegalArgumentException - if the row lengths of matrix differ.
ex: Stream.transpose(Stream(Stream(1,2,3), Stream(4,5,6))) → Stream(Stream(1,4), Stream(2,5), Stream(3,6))
static <T,U> Stream<U> unfoldRight(T seed, Function<? super T,Option<Tuple2<? extends U,? extends T>>> f)
None when it's
done generating the Stream, otherwise Some Tuple
of the element for the next call and the value to add to the
resulting Stream.
Example:
Stream.unfoldRight(10, x -> x == 0
? Option.none()
: Option.of(new Tuple2<>(x, x-1)));
// Stream(10, 9, 8, 7, 6, 5, 4, 3, 2, 1))
T - type of seedsU - type of unfolded valuesseed - the start value for the iterationf - the function to get the next step of the iterationNullPointerException - if f is nullstatic <T,U> Stream<U> unfoldLeft(T seed, Function<? super T,Option<Tuple2<? extends T,? extends U>>> f)
None when it's
done generating the Stream, otherwise Some Tuple
of the value to add to the resulting Stream and
the element for the next call.
Example:
Stream.unfoldLeft(10, x -> x == 0
? Option.none()
: Option.of(new Tuple2<>(x-1, x)));
// Stream(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))
T - type of seedsU - type of unfolded valuesseed - the start value for the iterationf - the function to get the next step of the iterationNullPointerException - if f is nullstatic <T> Stream<T> unfold(T seed, Function<? super T,Option<Tuple2<? extends T,? extends T>>> f)
None when it's
done generating the Stream, otherwise Some Tuple
of the value to add to the resulting Stream and
the element for the next call.
Example:
Stream.unfold(10, x -> x == 0
? Option.none()
: Option.of(new Tuple2<>(x-1, x)));
// Stream(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))
T - type of seeds and unfolded valuesseed - the start value for the iterationf - the function to get the next step of the iterationNullPointerException - if f is nullstatic <T> Stream<T> continually(T t)
T - Element typet - An elementt's.default Stream<T> append(T element)
Seqdefault Stream<T> appendAll(Iterable<? extends T> elements)
Seqdefault Stream<T> appendSelf(Function<? super Stream<T>,? extends Stream<T>> mapper)
mapper function.
Example:
Well known Scala code for Fibonacci infinite sequence
val fibs:Stream[Int] = 0 #:: 1 #:: (fibs zip fibs.tail).map{ t => t._1 + t._2 }
can be transformed to
Stream.of(0, 1).appendSelf(self -> self.zip(self.tail()).map(t -> t._1 + t._2));
mapper - an mapper@GwtIncompatible default List<T> asJava()
SeqList view on top of this Seq,
i.e. calling mutators will result in UnsupportedOperationException at runtime.
The difference to conversion methods toJava*() is that
java.util.List view throws UnsupportedOperationException before
checking method arguments. Java does handle this case inconsistently.asJava in interface Seq<T>Collection view on this Traversable.@GwtIncompatible default Stream<T> asJava(Consumer<? super List<T>> action)
Seq@GwtIncompatible default List<T> asJavaMutable()
SeqList view on top of this Seq,
i.e. all mutator methods of the List are implemented.asJavaMutable in interface Seq<T>Collection view on this Traversable.Seq.asJava()@GwtIncompatible default Stream<T> asJavaMutable(Consumer<? super List<T>> action)
SeqasJavaMutable in interface LinearSeq<T>asJavaMutable in interface Seq<T>action - A side-effecting unit of work that operates on a mutable java.util.List view.java.util.List view or a new instance of this type, if write operations are performed on the java.util.List view.Seq.asJavaMutable()default <R> Stream<R> collect(PartialFunction<? super T,? extends R> partialFunction)
TraversablepartialFunction by mapping the elements to type R.
More specifically, for each of this elements in iteration order first it is checked
partialFunction.isDefinedAt(element)
If the elements makes it through that filter, the mapped instance is added to the result collection
R newElement = partialFunction.apply(element)
Note:If this Traversable is ordered (i.e. extends Ordered,
the caller of collect has to ensure that the elements are comparable (i.e. extend Comparable).collect in interface LinearSeq<T>collect in interface Seq<T>collect in interface Traversable<T>R - The new element typepartialFunction - A function that is not necessarily defined of all elements of this traversable.Traversable instance containing elements of type Rdefault Stream<Stream<T>> combinations()
SeqExamples:
[].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
]
combinations in interface LinearSeq<T>combinations in interface Seq<T>default Stream<Stream<T>> combinations(int k)
Seqcombinations in interface LinearSeq<T>combinations in interface Seq<T>k - Size of subsetsdefault Iterator<Stream<T>> crossProduct(int power)
SeqExample:
// = ((A,A), (A,B), (A,C), ..., (B,A), (B,B), ..., (Z,Y), (Z,Z))
CharSeq.rangeClosed('A', 'Z').crossProduct(2);
Cartesian power of negative value will return empty iterator.
Example:
// = ()
CharSeq.rangeClosed('A', 'Z').crossProduct(-1);
crossProduct in interface LinearSeq<T>crossProduct in interface Seq<T>power - the number of cartesian multiplicationsdefault Stream<T> cycle()
Example:
// = 1, 2, 3, 1, 2, 3, 1, 2, 3, ...
Stream.of(1, 2, 3).cycle();
default Stream<T> cycle(int count)
count times.
Example:
// = empty
Stream.of(1, 2, 3).cycle(0);
// = 1, 2, 3
Stream.of(1, 2, 3).cycle(1);
// = 1, 2, 3, 1, 2, 3, 1, 2, 3
Stream.of(1, 2, 3).cycle(3);
count - the number of cycles to be performedcount times.default Stream<T> distinct()
Traversableequals.default Stream<T> distinctBy(Comparator<? super T> comparator)
Traversablecomparator.distinctBy in interface LinearSeq<T>distinctBy in interface Seq<T>distinctBy in interface Traversable<T>comparator - A comparatorTraversable containing this elements without duplicatesdefault <U> Stream<T> distinctBy(Function<? super T,? extends U> keyExtractor)
Traversableequals.
The elements of the result are determined in the order of their occurrence - first match wins.
distinctBy in interface LinearSeq<T>distinctBy in interface Seq<T>distinctBy in interface Traversable<T>U - key typekeyExtractor - A key extractorTraversable containing this elements without duplicatesdefault Stream<T> drop(int n)
Traversabledrop in interface LinearSeq<T>drop in interface Seq<T>drop in interface Traversable<T>n - The number of elements to drop.default Stream<T> dropUntil(Predicate<? super T> predicate)
TraversabledropUntil in interface LinearSeq<T>dropUntil in interface Seq<T>dropUntil in interface Traversable<T>predicate - A condition tested subsequently for this elements.default Stream<T> dropWhile(Predicate<? super T> predicate)
Traversable
Note: This is essentially the same as dropUntil(predicate.negate()).
It is intended to be used with method references, which cannot be negated directly.
dropWhile in interface LinearSeq<T>dropWhile in interface Seq<T>dropWhile in interface Traversable<T>predicate - A condition tested subsequently for this elements.default Stream<T> dropRight(int n)
TraversabledropRight in interface LinearSeq<T>dropRight in interface Seq<T>dropRight in interface Traversable<T>n - The number of elements to drop.default Stream<T> dropRightUntil(Predicate<? super T> predicate)
SeqdropRightUntil in interface LinearSeq<T>dropRightUntil in interface Seq<T>predicate - A condition tested subsequently for this elements, starting from the end.default Stream<T> dropRightWhile(Predicate<? super T> predicate)
Seq
Note: This is essentially the same as dropRightUntil(predicate.negate()).
It is intended to be used with method references, which cannot be negated directly.
dropRightWhile in interface LinearSeq<T>dropRightWhile in interface Seq<T>predicate - A condition tested subsequently for this elements, starting from the end.default Stream<T> filter(Predicate<? super T> predicate)
Traversabledefault Stream<T> reject(Predicate<? super T> predicate)
TraversableThe default implementation is equivalent to
filter(predicate.negate()default <U> Stream<U> flatMap(Function<? super T,? extends Iterable<? extends U>> mapper)
Traversabledefault T get(int index)
Seqdefault <C> Map<C,Stream<T>> groupBy(Function<? super T,? extends C> classifier)
TraversablegroupBy in interface LinearSeq<T>groupBy in interface Seq<T>groupBy in interface Traversable<T>C - classified class typeclassifier - A function which classifies elements into classesTraversable.arrangeBy(Function)default Iterator<Stream<T>> grouped(int size)
TraversableTraversable into fixed size blocks.
Let length be the length of this Iterable. Then grouped is defined as follows:
this.isEmpty(), the resulting Iterator is empty.size <= length, the resulting Iterator will contain length / size blocks of size
size and maybe a non-empty block of size length % size, if there are remaining elements.size > length, the resulting Iterator will contain one block of size length.
[].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]]
Please note that grouped(int) is a special case of Traversable.sliding(int, int), i.e.
grouped(size) is the same as sliding(size, size).default boolean hasDefiniteSize()
TraversableThis method should be implemented by classes only, i.e. not by interfaces.
hasDefiniteSize in interface Traversable<T>default int indexOf(T element, int from)
Seqdefault Stream<T> init()
Traversabledefault Option<Stream<T>> initOption()
TraversableOption.initOption in interface LinearSeq<T>initOption in interface Seq<T>initOption in interface Traversable<T>Some(traversable) or None if this is empty.default Stream<T> insert(int index, T element)
Seqdefault Stream<T> insertAll(int index, Iterable<? extends T> elements)
Seqdefault Stream<T> intersperse(T element)
Seqintersperse in interface LinearSeq<T>intersperse in interface Seq<T>element - An element.default boolean isAsync()
Stream is computed synchronously.default boolean isLazy()
Stream is computed lazily.default boolean isTraversableAgain()
TraversableThis method should be implemented by classes only, i.e. not by interfaces.
isTraversableAgain in interface Traversable<T>default T last()
Traversablelast in interface Traversable<T>default int lastIndexOf(T element, int end)
SeqlastIndexOf in interface Seq<T>element - an elementend - the end indexdefault int length()
Traversable
Same as Traversable.size().
length in interface Traversable<T>default <U> Stream<U> map(Function<? super T,? extends U> mapper)
TraversableTraversable to elements of a new type preserving their order, if any.default Stream<T> padTo(int length, T element)
SeqNote: lazily-evaluated Seq implementations need to process all elements in order to gather the overall length.
padTo in interface LinearSeq<T>padTo in interface Seq<T>length - the target lengthelement - the padding elementelement so that the resulting sequence has a length of at least length.default Stream<T> leftPadTo(int length, T element)
SeqNote: lazily-evaluated Seq implementations need to process all elements in order to gather the overall length.
leftPadTo in interface Seq<T>length - the target lengthelement - the padding elementelement so that the resulting sequence has a length of at least length.default Stream<T> orElse(Iterable<? extends T> other)
TraversableTraversable if it is nonempty, otherwise return the alternative.default Stream<T> orElse(Supplier<? extends Iterable<? extends T>> supplier)
TraversableTraversable if it is nonempty, otherwise return the result of evaluating supplier.default Stream<T> patch(int from, Iterable<? extends T> that, int replaced)
Seqdefault Tuple2<Stream<T>,Stream<T>> partition(Predicate<? super T> predicate)
TraversableTraversable by splitting this elements in two in distinct traversables
according to a predicate.partition in interface LinearSeq<T>partition in interface Seq<T>partition in interface Traversable<T>predicate - A predicate which classifies an element if it is in the first or the second traversable.Traversable contains all elements that satisfy the given predicate, the second Traversable contains all elements that don't. The original order of elements is preserved.default Stream<T> peek(Consumer<? super T> action)
Valueaction 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.default Stream<Stream<T>> permutations()
SeqExample:
[].permutations() = []
[1,2,3].permutations() = [
[1,2,3],
[1,3,2],
[2,1,3],
[2,3,1],
[3,1,2],
[3,2,1]
]
permutations in interface LinearSeq<T>permutations in interface Seq<T>default Stream<T> prepend(T element)
Seqdefault Stream<T> prependAll(Iterable<? extends T> elements)
SeqprependAll in interface LinearSeq<T>prependAll in interface Seq<T>elements - An Iterable of elementsdefault Stream<T> remove(T element)
Seqdefault Stream<T> removeFirst(Predicate<T> predicate)
SeqremoveFirst in interface LinearSeq<T>removeFirst in interface Seq<T>predicate - an predicatedefault Stream<T> removeLast(Predicate<T> predicate)
SeqremoveLast in interface LinearSeq<T>removeLast in interface Seq<T>predicate - an predicatedefault Stream<T> removeAt(int index)
Seqdefault Stream<T> removeAll(T element)
Seqdefault Stream<T> removeAll(Iterable<? extends T> elements)
Seq@Deprecated default Stream<T> removeAll(Predicate<? super T> predicate)
Seqdefault Stream<T> replace(T currentElement, T newElement)
Traversablereplace in interface LinearSeq<T>replace in interface Seq<T>replace in interface Traversable<T>currentElement - An element to be substituted.newElement - A replacement for currentElement.default Stream<T> replaceAll(T currentElement, T newElement)
TraversablereplaceAll in interface LinearSeq<T>replaceAll in interface Seq<T>replaceAll in interface Traversable<T>currentElement - An element to be substituted.newElement - A replacement for currentElement.default Stream<T> retainAll(Iterable<? extends T> elements)
Traversabledefault Stream<T> reverse()
Seqdefault Stream<T> rotateLeft(int n)
Seq
// = List(3, 4, 5, 1, 2)
List.of(1, 2, 3, 4, 5).rotateLeft(2);
rotateLeft in interface LinearSeq<T>rotateLeft in interface Seq<T>n - distance of left rotationdefault Stream<T> rotateRight(int n)
Seq
// = List(4, 5, 1, 2, 3)
List.of(1, 2, 3, 4, 5).rotateRight(2);
rotateRight in interface LinearSeq<T>rotateRight in interface Seq<T>n - distance of right rotationdefault Stream<T> scan(T zero, BiFunction<? super T,? super T,? extends T> operation)
Traversablescan in interface LinearSeq<T>scan in interface Seq<T>scan in interface Traversable<T>zero - neutral element for the operator opoperation - the associative operator for the scandefault <U> Stream<U> scanLeft(U zero, BiFunction<? super U,? super T,? extends U> operation)
TraversablescanLeft in interface LinearSeq<T>scanLeft in interface Seq<T>scanLeft in interface Traversable<T>U - the type of the elements in the resulting collectionzero - the initial valueoperation - the binary operator applied to the intermediate result and the elementdefault <U> Stream<U> scanRight(U zero, BiFunction<? super T,? super U,? extends U> operation)
TraversablescanRight in interface LinearSeq<T>scanRight in interface Seq<T>scanRight in interface Traversable<T>U - the type of the elements in the resulting collectionzero - the initial valueoperation - the binary operator applied to the intermediate result and the elementdefault Stream<T> shuffle()
Seqdefault Stream<T> slice(int beginIndex, int endIndex)
SeqbeginIndex and extends to the element at index endIndex - 1.
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 throws in some cases instead of returning a sequence.default Iterator<Stream<T>> slideBy(Function<? super T,?> classifier)
TraversableTraversable.
Each window contains elements with the same class, as determined by classifier. Two consecutive
values in this Traversable will be in the same window only if classifier returns equal
values for them. Otherwise, the values will constitute the last element of the previous window and the
first element of the next window.
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]]
default Iterator<Stream<T>> sliding(int size)
Traversablesize and step size 1 over this Traversable by calling
Traversable.sliding(int, int).default Iterator<Stream<T>> sliding(int size, int step)
Traversablesize and step size 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]]
default Stream<T> sorted()
SeqComparable, a java.lang.ClassCastException may be thrown.default Stream<T> sorted(Comparator<? super T> comparator)
SeqComparator. If this elements are not
Comparable, a java.lang.ClassCastException may be thrown.default <U extends Comparable<? super U>> Stream<T> sortBy(Function<? super T,? extends U> mapper)
Seqmapper.default <U> Stream<T> sortBy(Comparator<? super U> comparator, Function<? super T,? extends U> mapper)
Seqmapper.default Tuple2<Stream<T>,Stream<T>> span(Predicate<? super T> predicate)
Traversablepredicate and the second element is the remainder.default Tuple2<Stream<T>,Stream<T>> splitAt(int n)
SeqsplitAt(n) is equivalent to
Tuple.of(take(n), drop(n)).default Tuple2<Stream<T>,Stream<T>> splitAt(Predicate<? super T> predicate)
SeqPredicate, e.g. Tuple(init, element+tail).default Tuple2<Stream<T>,Stream<T>> splitAtInclusive(Predicate<? super T> predicate)
SeqPredicate, e.g. Tuple(init+element, tail).splitAtInclusive in interface Seq<T>predicate - An predicateTuple containing divided sequencesdefault String stringPrefix()
ValuestringPrefix in interface Value<T>default Stream<T> subSequence(int beginIndex)
SeqbeginIndex and extends to the end of this Seq.
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 is similar but does not throw.subSequence in interface LinearSeq<T>subSequence in interface Seq<T>beginIndex - the beginning index, inclusivedefault Stream<T> subSequence(int beginIndex, int endIndex)
SeqbeginIndex and extends to the element at index endIndex - 1.
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.subSequence in interface LinearSeq<T>subSequence in interface Seq<T>beginIndex - the beginning index, inclusiveendIndex - the end index, exclusiveStream<T> tail()
Traversabledefault Option<Stream<T>> tailOption()
TraversableOption.tailOption in interface LinearSeq<T>tailOption in interface Seq<T>tailOption in interface Traversable<T>Some(traversable) or None if this is empty.default Stream<T> take(int n)
Traversable
The result is equivalent to sublist(0, max(0, min(length(), n))) but does not throw if n < 0 or
n > length().
In the case of n < 0 the empty instance is returned, in the case of n > length() this is returned.
default Stream<T> takeUntil(Predicate<? super T> predicate)
Traversable
Note: This is essentially the same as takeWhile(predicate.negate()). It is intended to be used with
method references, which cannot be negated directly.
takeUntil in interface LinearSeq<T>takeUntil in interface Seq<T>takeUntil in interface Traversable<T>predicate - A condition tested subsequently for this elements.default Stream<T> takeWhile(Predicate<? super T> predicate)
TraversabletakeWhile in interface LinearSeq<T>takeWhile in interface Seq<T>takeWhile in interface Traversable<T>predicate - A condition tested subsequently for the contained elements.default Stream<T> takeRight(int n)
Traversable
The result is equivalent to sublist(max(0, min(length(), length() - n)), n), i.e. takeRight will not
throw if n < 0 or n > length().
In the case of n < 0 the empty instance is returned, in the case of n > length() this is returned.
takeRight in interface LinearSeq<T>takeRight in interface Seq<T>takeRight in interface Traversable<T>n - The number of elements to take.default Stream<T> takeRightUntil(Predicate<? super T> predicate)
SeqtakeRightUntil in interface LinearSeq<T>takeRightUntil in interface Seq<T>predicate - A condition tested subsequently for this elements, starting from the end.default Stream<T> takeRightWhile(Predicate<? super T> predicate)
Seq
Note: This is essentially the same as takeRightUntil(predicate.negate()).
It is intended to be used with method references, which cannot be negated directly.
takeRightWhile in interface LinearSeq<T>takeRightWhile in interface Seq<T>predicate - A condition tested subsequently for this elements, starting from the end.default <U> U transform(Function<? super Stream<T>,? extends U> f)
Stream.U - Type of transformation resultf - A transformationUNullPointerException - if f is nulldefault <T1,T2> Tuple2<Stream<T1>,Stream<T2>> unzip(Function<? super T,Tuple2<? extends T1,? extends T2>> unzipper)
Traversableunzip in interface LinearSeq<T>unzip in interface Seq<T>unzip in interface Traversable<T>T1 - 1st element type of a pair returned by unzipperT2 - 2nd element type of a pair returned by unzipperunzipper - a function which converts elements of this to pairsdefault <T1,T2,T3> Tuple3<Stream<T1>,Stream<T2>,Stream<T3>> unzip3(Function<? super T,Tuple3<? extends T1,? extends T2,? extends T3>> unzipper)
Traversableunzip3 in interface Seq<T>unzip3 in interface Traversable<T>T1 - 1st element type of a triplet returned by unzipperT2 - 2nd element type of a triplet returned by unzipperT3 - 3rd element type of a triplet returned by unzipperunzipper - a function which converts elements of this to pairsdefault Stream<T> update(int index, T element)
Seqdefault Stream<T> update(int index, Function<? super T,? extends T> updater)
Seqdefault <U> Stream<Tuple2<T,U>> zip(Iterable<? extends U> that)
Traversable
The length of the returned traversable is the minimum of the lengths of this traversable and that
iterable.
zip in interface LinearSeq<T>zip in interface Seq<T>zip in interface Traversable<T>U - The type of the second half of the returned pairs.that - The Iterable providing the second half of each result pair.that iterable.default <U,R> Stream<R> zipWith(Iterable<? extends U> that, BiFunction<? super T,? super U,? extends R> mapper)
Traversable
The length of the returned traversable is the minimum of the lengths of this traversable and that
iterable.
zipWith in interface LinearSeq<T>zipWith in interface Seq<T>zipWith in interface Traversable<T>U - The type of the second parameter of the mapper.R - The type of the mapped elements.that - The Iterable providing the second parameter of the mapper.mapper - a mapper.that iterable.default <U> Stream<Tuple2<T,U>> zipAll(Iterable<? extends U> iterable, T thisElem, U thatElem)
Traversable
The length of the returned traversable is the maximum of the lengths of this traversable and that
iterable.
Special case: if this traversable is shorter than that elements, and that elements contains duplicates, the resulting traversable may be shorter than the maximum of the lengths of this and that because a traversable contains an element at most once.
If this Traversable is shorter than that, thisElem values are used to fill the result. If that is shorter than this Traversable, thatElem values are used to fill the result.
zipAll in interface LinearSeq<T>zipAll in interface Seq<T>zipAll in interface Traversable<T>U - The type of the second half of the returned pairs.iterable - The Iterable providing the second half of each result pair.thisElem - The element to be used to fill up the result if this traversable is shorter than that.thatElem - The element to be used to fill up the result if that is shorter than this traversable.default Stream<Tuple2<T,Integer>> zipWithIndex()
TraversablezipWithIndex in interface LinearSeq<T>zipWithIndex in interface Seq<T>zipWithIndex in interface Traversable<T>default <U> Stream<U> zipWithIndex(BiFunction<? super T,? super Integer,? extends U> mapper)
Traversable
The length of the returned traversable is the minimum of the lengths of this traversable and that
iterable.
zipWithIndex in interface LinearSeq<T>zipWithIndex in interface Seq<T>zipWithIndex in interface Traversable<T>U - The type of the mapped elements.mapper - a mapper.that iterable.default Stream<T> extend(T next)
Stream with a constantly repeated value.next - value with which the stream should be extendedStream composed from this stream extended with a Stream of provided valuedefault Stream<T> extend(Supplier<? extends T> nextSupplier)
Stream with values provided by a SuppliernextSupplier - a supplier which will provide values for extending a streamStream composed from this stream extended with values provided by the supplierdefault Stream<T> extend(Function<? super T,? extends T> nextFunction)
Stream with a Stream of values created by applying
consecutively provided Function to the last element of the original Stream.nextFunction - a function which calculates the next value basing on the previous valueStream composed from this stream extended with values calculated by the provided functionCopyright © 2019. All Rights Reserved.