T - Component typepublic interface Iterator<T> extends java.util.Iterator<T>, Traversable<T>
io.vavr.collection.Iterator is a compositional replacement for java.util.Iterator
whose purpose is to iterate once over a sequence of elements.
Note: Iterators encapsulate mutable state. They are not meant to be used concurrently by different threads. Do not reuse Iterators, e.g. after passing to List.ofAll(Iterable).
There are two abstract methods: hasNext for checking if there is a next element available,
and next which removes the next element from the iterator and returns it. They can be called
an arbitrary amount of times. If hasNext returns false, a call of next will throw
a NoSuchElementException.
Caution: Other methods than hasNext and next can be called only once (exclusively).
More specifically, after calling a method it cannot be guaranteed that the next call will succeed.
An Iterator that can be only used once because it is a traversal pointer into a collection, and not a collection itself.
| Modifier and Type | Method and Description |
|---|---|
default <R> Iterator<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> Iterator<T> |
concat(java.lang.Iterable<? extends java.lang.Iterable<? extends T>> iterables)
Creates an Iterator which traverses along the concatenation of the given iterables.
|
static <T> Iterator<T> |
concat(java.lang.Iterable<? extends T>... iterables)
Creates an Iterator which traverses along the concatenation of the given iterables.
|
default Iterator<T> |
concat(java.util.Iterator<? extends T> that) |
static <T> Iterator<T> |
continually(java.util.function.Supplier<? extends T> supplier)
Generates an infinite iterator using a value Supplier.
|
static <T> Iterator<T> |
continually(T t)
Creates an infinite iterator returning the given element.
|
default Iterator<T> |
distinct()
Returns a new version of this which contains no duplicates.
|
default Iterator<T> |
distinctBy(java.util.Comparator<? super T> comparator)
Returns a new version of this which contains no duplicates.
|
default <U> Iterator<T> |
distinctBy(java.util.function.Function<? super T,? extends U> keyExtractor)
Returns a new version of this which contains no duplicates.
|
default Iterator<T> |
drop(int n)
Removes up to n elements from this iterator.
|
default Iterator<T> |
dropRight(int n)
Drops the last n elements of this or all elements, if this length < n.
|
default Iterator<T> |
dropUntil(java.util.function.Predicate<? super T> predicate)
Drops elements until the predicate holds for the current element.
|
default Iterator<T> |
dropWhile(java.util.function.Predicate<? super T> predicate)
Drops elements while the predicate holds for the current element.
|
static <T> Iterator<T> |
empty()
Returns the singleton instance of the empty
Iterator. |
static <T> Iterator<T> |
fill(int n,
java.util.function.Supplier<? extends T> s)
Returns an Iterator on a sequence of
n values supplied by a given Supplier s. |
static <T> Iterator<T> |
fill(int n,
T element)
Returns a Iterator containing
n times the given element |
default Iterator<T> |
filter(java.util.function.Predicate<? super T> predicate)
Returns an Iterator that contains elements that satisfy the given
predicate. |
default Iterator<T> |
filterNot(java.util.function.Predicate<? super T> predicate)
Returns an Iterator that contains elements that not satisfy the given
predicate. |
default Option<T> |
findLast(java.util.function.Predicate<? super T> predicate)
Returns the last element of this which satisfies the given predicate.
|
default <U> Iterator<U> |
flatMap(java.util.function.Function<? super T,? extends java.lang.Iterable<? extends U>> mapper)
Maps the elements of this Iterator to Iterables and concats their iterators.
|
default <U> U |
foldRight(U zero,
java.util.function.BiFunction<? super T,? super U,? extends U> f)
Folds this elements from the right, starting with
zero and successively calling combine. |
static Iterator<java.lang.Integer> |
from(int value)
Returns an infinite iterator of int values starting from
value. |
static Iterator<java.lang.Integer> |
from(int value,
int step)
Returns an infinite iterator of int values starting from
value and spaced by step. |
static Iterator<java.lang.Long> |
from(long value)
Returns an infinite iterator of long values starting from
value. |
static Iterator<java.lang.Long> |
from(long value,
long step)
Returns an infinite iterator of long values starting from
value and spaced by step. |
default T |
get()
Gets the first value in iteration order if this
Traversable is not empty, otherwise throws. |
default <C> Map<C,Iterator<T>> |
groupBy(java.util.function.Function<? super T,? extends C> classifier)
Groups this elements by classifying the elements.
|
default Iterator<Seq<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 T |
head()
Returns the first element of a non-empty Traversable.
|
default Iterator<T> |
init()
Dual of Traversable.tail(), returning all elements except the last.
|
default Option<Iterator<T>> |
initOption()
Dual of Traversable.tailOption(), returning all elements except the last as
Option. |
default Iterator<T> |
intersperse(T element)
Inserts an element between all elements of this Iterator.
|
default boolean |
isAsync()
An
Iterator is computed synchronously. |
default boolean |
isEmpty()
Checks if this Traversable is empty.
|
default boolean |
isLazy()
An
Iterator is computed lazily. |
default boolean |
isSequential()
Checks if the elements of this Traversable appear in encounter order.
|
default boolean |
isTraversableAgain()
Checks if this Traversable can be repeatedly traversed.
|
static <T> Iterator<T> |
iterate(java.util.function.Supplier<? extends Option<? extends T>> supplier)
Creates an iterator that repeatedly invokes the supplier
while it's a
Some and end on the first None |
static <T> Iterator<T> |
iterate(T seed,
java.util.function.Function<? super T,? extends T> f)
Generates an infinite iterator using a function to calculate the next value
based on the previous.
|
default Iterator<T> |
iterator()
An iterator by means of head() and tail().
|
default T |
last()
Dual of Traversable.head(), returning the last element.
|
default int |
length()
Computes the number of elements of this Traversable.
|
default <U> Iterator<U> |
map(java.util.function.Function<? super T,? extends U> mapper)
Maps the elements of this Iterator lazily using the given
mapper. |
static <T> Iterator<T> |
narrow(Iterator<? extends T> iterator)
Narrows a widened
Iterator<? extends T> to Iterator<T>
by performing a type-safe cast. |
default Option<T> |
nextOption()
A safe alternative to
Iterator.next() that is equivalent to |
static <T> Iterator<T> |
of(T... elements)
Creates an
Iterator which iterates over the given elements. |
static <T> Iterator<T> |
of(T element)
Creates an
Iterator which iterates over the given element. |
static Iterator<java.lang.Boolean> |
ofAll(boolean... elements)
Creates an Iterator from boolean values.
|
static Iterator<java.lang.Byte> |
ofAll(byte... elements)
Creates an Iterator from byte values.
|
static Iterator<java.lang.Character> |
ofAll(char... elements)
Creates an Iterator from char values.
|
static Iterator<java.lang.Double> |
ofAll(double... elements)
Creates ann Iterator from double values.
|
static Iterator<java.lang.Float> |
ofAll(float... elements)
Creates an Iterator from float values.
|
static Iterator<java.lang.Integer> |
ofAll(int... elements)
Creates an Iterator from int values.
|
static <T> Iterator<T> |
ofAll(java.lang.Iterable<? extends T> iterable)
Creates a
Iterator based on the given Iterable. |
static <T> Iterator<T> |
ofAll(java.util.Iterator<? extends T> iterator)
Creates an Iterator based on the given Iterator by
delegating calls of
hasNext() and next() to it. |
static Iterator<java.lang.Long> |
ofAll(long... elements)
Creates an Iterator from long values.
|
static Iterator<java.lang.Short> |
ofAll(short... elements)
Creates an Iterator from short values.
|
default Iterator<T> |
orElse(java.lang.Iterable<? extends T> other)
Returns this
Traversable if it is nonempty, otherwise return the alternative. |
default Iterator<T> |
orElse(java.util.function.Supplier<? extends java.lang.Iterable<? extends T>> supplier)
Returns this
Traversable if it is nonempty, otherwise return the result of evaluating supplier. |
default Tuple2<Iterator<T>,Iterator<T>> |
partition(java.util.function.Predicate<? super T> predicate)
Creates a partition of this
Traversable by splitting this elements in two in distinct traversables
according to a predicate. |
default Iterator<T> |
peek(java.util.function.Consumer<? super T> action)
Performs the given
action on the first element if this is an eager implementation. |
static Iterator<java.lang.Character> |
range(char from,
char toExclusive)
Creates an Iterator of characters starting from
from, extending to toExclusive - 1. |
static Iterator<java.lang.Integer> |
range(int from,
int toExclusive)
Creates an Iterator of int numbers starting from
from, extending to toExclusive - 1. |
static Iterator<java.lang.Long> |
range(long from,
long toExclusive)
Creates an Iterator of long numbers starting from
from, extending to toExclusive - 1. |
static Iterator<java.math.BigDecimal> |
rangeBy(java.math.BigDecimal from,
java.math.BigDecimal toExclusive,
java.math.BigDecimal step) |
static Iterator<java.lang.Character> |
rangeBy(char from,
char toExclusive,
int step)
Creates an Iterator of characters starting from
from, extending to toExclusive - 1,
with step. |
static Iterator<java.lang.Double> |
rangeBy(double from,
double toExclusive,
double step) |
static Iterator<java.lang.Integer> |
rangeBy(int from,
int toExclusive,
int step)
Creates an Iterator of int numbers starting from
from, extending to toExclusive - 1,
with step. |
static Iterator<java.lang.Long> |
rangeBy(long from,
long toExclusive,
long step)
Creates an Iterator of long numbers starting from
from, extending to toExclusive - 1,
with step. |
static Iterator<java.lang.Character> |
rangeClosed(char from,
char toInclusive)
Creates an Iterator of characters starting from
from, extending to toInclusive. |
static Iterator<java.lang.Integer> |
rangeClosed(int from,
int toInclusive)
Creates an Iterator of int numbers starting from
from, extending to toInclusive. |
static Iterator<java.lang.Long> |
rangeClosed(long from,
long toInclusive)
Creates an Iterator of long numbers starting from
from, extending to toInclusive. |
static Iterator<java.lang.Character> |
rangeClosedBy(char from,
char toInclusive,
int step)
Creates an Iterator of characters starting from
from, extending to toInclusive,
with step. |
static Iterator<java.lang.Double> |
rangeClosedBy(double from,
double toInclusive,
double step) |
static Iterator<java.lang.Integer> |
rangeClosedBy(int from,
int toInclusive,
int step)
Creates an Iterator of int numbers starting from
from, extending to toInclusive,
with step. |
static Iterator<java.lang.Long> |
rangeClosedBy(long from,
long toInclusive,
long step)
Creates an Iterator of long numbers starting from
from, extending to toInclusive,
with step. |
default T |
reduceLeft(java.util.function.BiFunction<? super T,? super T,? extends T> op)
Accumulates the elements of this Traversable by successively calling the given operation
op from the left. |
default T |
reduceRight(java.util.function.BiFunction<? super T,? super T,? extends T> op)
Accumulates the elements of this Traversable by successively calling the given operation
op from the right. |
default Iterator<T> |
replace(T currentElement,
T newElement)
Replaces the first occurrence (if exists) of the given currentElement with newElement.
|
default Iterator<T> |
replaceAll(T currentElement,
T newElement)
Replaces all occurrences of the given currentElement with newElement.
|
default Iterator<T> |
retainAll(java.lang.Iterable<? extends T> elements)
Keeps all occurrences of the given elements from this.
|
default Traversable<T> |
scan(T zero,
java.util.function.BiFunction<? super T,? super T,? extends T> operation)
Computes a prefix scan of the elements of the collection.
|
default <U> Iterator<U> |
scanLeft(U zero,
java.util.function.BiFunction<? super U,? super T,? extends U> operation)
Produces a collection containing cumulative results of applying the
operator going left to right.
|
default <U> Iterator<U> |
scanRight(U zero,
java.util.function.BiFunction<? super T,? super U,? extends U> operation)
Produces a collection containing cumulative results of applying the
operator going right to left.
|
default Iterator<Seq<T>> |
slideBy(java.util.function.Function<? super T,?> classifier)
Slides a non-overlapping window of a variable size over this
Traversable. |
default Iterator<Seq<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<Seq<T>> |
sliding(int size,
int step)
Slides a window of a specific
size and step size over this Traversable. |
default Tuple2<Iterator<T>,Iterator<T>> |
span(java.util.function.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 java.lang.String |
stringPrefix()
Returns the name of this Value type, which is used by toString().
|
static <T> Iterator<T> |
tabulate(int n,
java.util.function.Function<? super java.lang.Integer,? extends T> f)
Returns an Iterator on a sequence of
n values of a given Function f
over a range of integer values from 0 to n - 1. |
default Iterator<T> |
tail()
Drops the first element of a non-empty Traversable.
|
default Option<Iterator<T>> |
tailOption()
Drops the first element of a non-empty Traversable and returns an
Option. |
default Iterator<T> |
take(int n)
Take the first n elements from this iterator.
|
default Iterator<T> |
takeRight(int n)
Takes the last n elements of this or all elements, if this length < n.
|
default Iterator<T> |
takeUntil(java.util.function.Predicate<? super T> predicate)
Takes elements until the predicate holds for the current element.
|
default Iterator<T> |
takeWhile(java.util.function.Predicate<? super T> predicate)
Takes elements while the predicate holds for the current element.
|
default Seq<T> |
toSeq()
Converts this to a
Seq. |
default <U> U |
transform(java.util.function.Function<? super Iterator<T>,? extends U> f)
Transforms this
Iterator. |
static <T> Iterator<T> |
unfold(T seed,
java.util.function.Function<? super T,Option<Tuple2<? extends T,? extends T>>> f)
Creates an iterator from a seed value and a function.
|
static <T,U> Iterator<U> |
unfoldLeft(T seed,
java.util.function.Function<? super T,Option<Tuple2<? extends T,? extends U>>> f)
Creates an iterator from a seed value and a function.
|
static <T,U> Iterator<U> |
unfoldRight(T seed,
java.util.function.Function<? super T,Option<Tuple2<? extends U,? extends T>>> f)
Creates an iterator from a seed value and a function.
|
default <T1,T2> Tuple2<Iterator<T1>,Iterator<T2>> |
unzip(java.util.function.Function<? super T,? extends T1> unzipper1,
java.util.function.Function<? super T,? extends T2> unzipper2)
Unzips this elements by mapping this elements to a pair of distinct sets.
|
default <T1,T2,T3> Tuple3<Iterator<T1>,Iterator<T2>,Iterator<T3>> |
unzip3(java.util.function.Function<? super T,? extends T1> unzipper1,
java.util.function.Function<? super T,? extends T2> unzipper2,
java.util.function.Function<? super T,? extends T3> unzipper3)
Unzips this elements by mapping this elements to three distinct sets.
|
default <U> Iterator<Tuple2<T,U>> |
zip(java.lang.Iterable<? extends U> that)
Returns a traversable formed from this traversable and another Iterable collection by combining
corresponding elements in pairs.
|
default <U> Iterator<Tuple2<T,U>> |
zipAll(java.lang.Iterable<? extends U> that,
T thisElem,
U thatElem)
Returns a traversable formed from this traversable and another Iterable by combining corresponding elements in
pairs.
|
default <U,R> Iterator<R> |
zipWith(java.lang.Iterable<? extends U> that,
java.util.function.BiFunction<? super T,? super U,? extends R> mapper)
Returns a traversable formed from this traversable and another Iterable collection by mapping elements.
|
default Iterator<Tuple2<T,java.lang.Integer>> |
zipWithIndex()
Zips this traversable with its indices.
|
default <U> Iterator<U> |
zipWithIndex(java.util.function.BiFunction<? super T,? super java.lang.Integer,? extends U> mapper)
Zips this traversable with its indices by applying mapper provided.
|
arrangeBy, average, containsAll, count, equals, existsUnique, find, fold, foldLeft, forEachWithIndex, hashCode, headOption, isDistinct, isOrdered, isSingleValued, lastOption, max, maxBy, maxBy, min, minBy, minBy, mkCharSeq, mkCharSeq, mkCharSeq, mkString, mkString, mkString, narrow, nonEmpty, product, reduce, reduceLeftOption, reduceOption, reduceRightOption, single, singleOption, size, spliterator, sum, toLinkedMap, toMap, toSortedMap, toSortedMapcollect, 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, toVector@SafeVarargs static <T> Iterator<T> concat(java.lang.Iterable<? extends T>... iterables)
T - Component type.iterables - The iterablesio.vavr.collection.Iteratorstatic <T> Iterator<T> concat(java.lang.Iterable<? extends java.lang.Iterable<? extends T>> iterables)
T - Component type.iterables - The iterable of iterablesio.vavr.collection.Iteratorstatic <T> Iterator<T> empty()
Iterator.
A call to Iterator.hasNext() will always return false.
A call to Iterator.next() will always throw a NoSuchElementException.
T - Element typeIteratorstatic <T> Iterator<T> narrow(Iterator<? extends T> iterator)
Iterator<? extends T> to Iterator<T>
by performing a type-safe cast. This is eligible because immutable/read-only
collections are covariant.T - Component type of the Iterator.iterator - An Iterator.iterator instance as narrowed type Iterator<T>.static <T> Iterator<T> of(T element)
Iterator which iterates over the given element.T - Element typeelement - An elementIterator@SafeVarargs static <T> Iterator<T> of(T... elements)
Iterator which iterates over the given elements.
Iterator<Integer> iterator = Iterator.of(1, 2, 3);
T - Element typeelements - Zero or more elementsIterator, if elements.length == 0,
otherwise a new Iterator.java.lang.NullPointerException - if elements is nullstatic <T> Iterator<T> ofAll(java.lang.Iterable<? extends T> iterable)
Iterator based on the given Iterable. This is a convenience method for
Iterator.ofAll(iterable.iterator().T - Component type.iterable - A Iterableio.vavr.collection.Iteratorstatic <T> Iterator<T> ofAll(java.util.Iterator<? extends T> iterator)
hasNext() and next() to it.T - Component type.iterator - A Iteratorio.vavr.collection.Iteratorstatic Iterator<java.lang.Boolean> ofAll(boolean... elements)
elements - boolean valuesjava.lang.NullPointerException - if elements is nullstatic Iterator<java.lang.Byte> ofAll(byte... elements)
elements - byte valuesjava.lang.NullPointerException - if elements is nullstatic Iterator<java.lang.Character> ofAll(char... elements)
elements - char valuesjava.lang.NullPointerException - if elements is nullstatic Iterator<java.lang.Double> ofAll(double... elements)
elements - double valuesjava.lang.NullPointerException - if elements is nullstatic Iterator<java.lang.Float> ofAll(float... elements)
elements - float valuesjava.lang.NullPointerException - if elements is nullstatic Iterator<java.lang.Integer> ofAll(int... elements)
elements - int valuesjava.lang.NullPointerException - if elements is nullstatic Iterator<java.lang.Long> ofAll(long... elements)
elements - long valuesjava.lang.NullPointerException - if elements is nullstatic Iterator<java.lang.Short> ofAll(short... elements)
elements - short valuesjava.lang.NullPointerException - if elements is nullstatic <T> Iterator<T> tabulate(int n, java.util.function.Function<? super java.lang.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 Iteratorn - The number of elementsf - The Function computing element valuesf(0),f(1), ..., f(n - 1)java.lang.NullPointerException - if f is nullstatic <T> Iterator<T> fill(int n, java.util.function.Supplier<? extends T> s)
n values supplied by a given Supplier s.T - Component type of the Iteratorn - The number of elementss - The Supplier computing element valuesn elements, where each element contains the result supplied by s.java.lang.NullPointerException - if s is nullstatic <T> Iterator<T> fill(int n, T element)
n times the given elementT - Component type of the Iteratorn - The number of elementselement - The elementn sequence elements, where each element is the given element.static Iterator<java.lang.Character> range(char from, char toExclusive)
from, extending to toExclusive - 1.
Examples:
Iterator.range('a', 'c') // = ('a', 'b')
Iterator.range('c', 'a') // = ()
from - the first charactertoExclusive - the successor of the last characterfrom >= toExclusivestatic Iterator<java.lang.Character> rangeBy(char from, char toExclusive, int step)
from, extending to toExclusive - 1,
with step.
Examples:
Iterator.rangeBy('a', 'c', 1) // = ('a', 'b')
Iterator.rangeBy('a', 'd', 2) // = ('a', 'c')
Iterator.rangeBy('d', 'a', -2) // = ('d', 'b')
Iterator.rangeBy('d', 'a', 2) // = ()
from - the first charactertoExclusive - the successor of the last character if step > 0, the predecessor of the last character if step < 0step - the stepsignum(step) == signum(from - toExclusive).java.lang.IllegalArgumentException - if step is zerostatic Iterator<java.lang.Double> rangeBy(double from, double toExclusive, double step)
static Iterator<java.math.BigDecimal> rangeBy(java.math.BigDecimal from, java.math.BigDecimal toExclusive, java.math.BigDecimal step)
static Iterator<java.lang.Integer> range(int from, int toExclusive)
from, extending to toExclusive - 1.
Examples:
Iterator.range(0, 0) // = ()
Iterator.range(2, 0) // = ()
Iterator.range(-2, 2) // = (-2, -1, 0, 1)
from - the first numbertoExclusive - the last number + 1from >= toExclusivestatic Iterator<java.lang.Integer> rangeBy(int from, int toExclusive, int step)
from, extending to toExclusive - 1,
with step.
Examples:
Iterator.rangeBy(1, 3, 1) // = (1, 2)
Iterator.rangeBy(1, 4, 2) // = (1, 3)
Iterator.rangeBy(4, 1, -2) // = (4, 2)
Iterator.rangeBy(4, 1, 2) // = ()
from - the first numbertoExclusive - the last number + 1 if step > 0, the last number - 1 if step < 0step - the step(from == toExclusive) || (step * (from - toExclusive) > 0).java.lang.IllegalArgumentException - if step is zerostatic Iterator<java.lang.Long> range(long from, long toExclusive)
from, extending to toExclusive - 1.
Examples:
Iterator.range(0L, 0L) // = ()
Iterator.range(2L, 0L) // = ()
Iterator.range(-2L, 2L) // = (-2L, -1L, 0L, 1L)
from - the first numbertoExclusive - the last number + 1from >= toExclusivestatic Iterator<java.lang.Long> rangeBy(long from, long toExclusive, long step)
from, extending to toExclusive - 1,
with step.
Examples:
Iterator.rangeBy(1L, 3L, 1L) // = (1L, 2L)
Iterator.rangeBy(1L, 4L, 2L) // = (1L, 3L)
Iterator.rangeBy(4L, 1L, -2L) // = (4L, 2L)
Iterator.rangeBy(4L, 1L, 2L) // = ()
from - the first numbertoExclusive - the last number + 1 if step > 0, the last number - 1 if step < 0step - the step(from == toExclusive) || (step * (from - toExclusive) > 0).java.lang.IllegalArgumentException - if step is zerostatic Iterator<java.lang.Character> rangeClosed(char from, char toInclusive)
from, extending to toInclusive.
Examples:
Iterator.rangeClosed('a', 'c') // = ('a', 'b', 'c')
Iterator.rangeClosed('c', 'a') // = ()
from - the first charactertoInclusive - the last characterfrom > toInclusivestatic Iterator<java.lang.Character> rangeClosedBy(char from, char toInclusive, int step)
from, extending to toInclusive,
with step.
Examples:
Iterator.rangeClosedBy('a', 'c', 1) // = ('a', 'b', 'c')
Iterator.rangeClosedBy('a', 'd', 2) // = ('a', 'c')
Iterator.rangeClosedBy('d', 'a', -2) // = ('d', 'b')
Iterator.rangeClosedBy('d', 'a', 2) // = ()
from - the first charactertoInclusive - the last characterstep - the stepsignum(step) == signum(from - toInclusive).java.lang.IllegalArgumentException - if step is zerostatic Iterator<java.lang.Double> rangeClosedBy(double from, double toInclusive, double step)
static Iterator<java.lang.Integer> rangeClosed(int from, int toInclusive)
from, extending to toInclusive.
Examples:
Iterator.rangeClosed(0, 0) // = (0)
Iterator.rangeClosed(2, 0) // = ()
Iterator.rangeClosed(-2, 2) // = (-2, -1, 0, 1, 2)
from - the first numbertoInclusive - the last numberfrom > toInclusivestatic Iterator<java.lang.Integer> rangeClosedBy(int from, int toInclusive, int step)
from, extending to toInclusive,
with step.
Examples:
Iterator.rangeClosedBy(1, 3, 1) // = (1, 2, 3)
Iterator.rangeClosedBy(1, 4, 2) // = (1, 3)
Iterator.rangeClosedBy(4, 1, -2) // = (4, 2)
Iterator.rangeClosedBy(4, 1, 2) // = ()
from - the first numbertoInclusive - the last numberstep - the stepsignum(step) == signum(from - toInclusive).java.lang.IllegalArgumentException - if step is zerostatic Iterator<java.lang.Long> rangeClosed(long from, long toInclusive)
from, extending to toInclusive.
Examples:
Iterator.rangeClosed(0L, 0L) // = (0L)
Iterator.rangeClosed(2L, 0L) // = ()
Iterator.rangeClosed(-2L, 2L) // = (-2L, -1L, 0L, 1L, 2L)
from - the first numbertoInclusive - the last numberfrom > toInclusivestatic Iterator<java.lang.Long> rangeClosedBy(long from, long toInclusive, long step)
from, extending to toInclusive,
with step.
Examples:
Iterator.rangeClosedBy(1L, 3L, 1L) // = (1L, 2L, 3L)
Iterator.rangeClosedBy(1L, 4L, 2L) // = (1L, 3L)
Iterator.rangeClosedBy(4L, 1L, -2L) // = (4L, 2L)
Iterator.rangeClosedBy(4L, 1L, 2L) // = ()
from - the first numbertoInclusive - the last numberstep - the stepsignum(step) == signum(from - toInclusive).java.lang.IllegalArgumentException - if step is zerostatic Iterator<java.lang.Integer> from(int value)
value.
The Iterator extends to Integer.MIN_VALUE when passing Integer.MAX_VALUE.
value - a start int valueIterator of int values starting from fromstatic Iterator<java.lang.Integer> from(int value, int step)
value and spaced by step.
The Iterator extends to Integer.MIN_VALUE when passing Integer.MAX_VALUE.
value - a start int valuestep - the step by which to advance on each iterationIterator of int values starting from fromstatic Iterator<java.lang.Long> from(long value)
value.
The Iterator extends to Long.MIN_VALUE when passing Long.MAX_VALUE.
value - a start long valueIterator of long values starting from fromstatic Iterator<java.lang.Long> from(long value, long step)
value and spaced by step.
The Iterator extends to Long.MIN_VALUE when passing Long.MAX_VALUE.
value - a start long valuestep - the step by which to advance on each iterationIterator of long values starting from fromstatic <T> Iterator<T> continually(java.util.function.Supplier<? extends T> supplier)
T - value typesupplier - A Supplier of iterator valuesIteratorstatic <T> Iterator<T> iterate(java.util.function.Supplier<? extends Option<? extends T>> supplier)
Some and end on the first NoneT - value typesupplier - A Supplier of iterator valuesIteratorjava.lang.NullPointerException - if supplier produces null valuestatic <T> Iterator<T> iterate(T seed, java.util.function.Function<? super T,? extends T> f)
T - value typeseed - The first value in the iteratorf - A function to calculate the next value based on the previousIteratorstatic <T> Iterator<T> continually(T t)
T - Element typet - An elementt's.default <R> Iterator<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 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 Iterator<T> intersperse(T element)
element - An element.default <U> U transform(java.util.function.Function<? super Iterator<T>,? extends U> f)
Iterator.U - Type of transformation resultf - A transformationUjava.lang.NullPointerException - if f is nulldefault <U> Iterator<Tuple2<T,U>> zip(java.lang.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 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> Iterator<R> zipWith(java.lang.Iterable<? extends U> that, java.util.function.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 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> Iterator<Tuple2<T,U>> zipAll(java.lang.Iterable<? extends U> that, 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 Traversable<T>U - The type of the second half of the returned pairs.that - 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 Iterator<Tuple2<T,java.lang.Integer>> zipWithIndex()
TraversablezipWithIndex in interface Traversable<T>default <U> Iterator<U> zipWithIndex(java.util.function.BiFunction<? super T,? super java.lang.Integer,? extends U> mapper)
TraversablezipWithIndex in interface Traversable<T>U - The type of the mapped elements.mapper - a mapper.default <T1,T2> Tuple2<Iterator<T1>,Iterator<T2>> unzip(java.util.function.Function<? super T,? extends T1> unzipper1, java.util.function.Function<? super T,? extends T2> unzipper2)
Traversableunzip in interface Traversable<T>T1 - element type returned by unzipper1T2 - element type returned by unzipper2unzipper1 - a function which converts elements of this to elements of first setunzipper2 - a function which converts elements of this to elements of second setdefault <T1,T2,T3> Tuple3<Iterator<T1>,Iterator<T2>,Iterator<T3>> unzip3(java.util.function.Function<? super T,? extends T1> unzipper1, java.util.function.Function<? super T,? extends T2> unzipper2, java.util.function.Function<? super T,? extends T3> unzipper3)
Traversableunzip3 in interface Traversable<T>T1 - element type returned by unzipper1T2 - element type returned by unzipper2T3 - element type returned by unzipper3unzipper1 - a function which converts elements of this to first setunzipper2 - a function which converts elements of this to second setunzipper3 - a function which converts elements of this to third setIterator to iterate over elements of sets split by unzipper1, unzipper2, unzipper3static <T> Iterator<T> unfold(T seed, java.util.function.Function<? super T,Option<Tuple2<? extends T,? extends T>>> f)
None when it's
done generating elements, otherwise Some Tuple
of the value to add to the resulting iterator and
the element for the next call.
Example:
Iterator.unfold(10, x -> x == 0
? Option.none()
: Option.of(new Tuple2<>(x-1, x)));
// List(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 iterationjava.lang.NullPointerException - if f is nullstatic <T,U> Iterator<U> unfoldLeft(T seed, java.util.function.Function<? super T,Option<Tuple2<? extends T,? extends U>>> f)
None when it's
done generating elements, otherwise Some Tuple
of the value to add to the resulting iterator and
the element for the next call.
Example:
Iterator.unfoldLeft(10, x -> x == 0
? Option.none()
: Option.of(new Tuple2<>(x-1, x)));
// List(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 iterationjava.lang.NullPointerException - if f is nullstatic <T,U> Iterator<U> unfoldRight(T seed, java.util.function.Function<? super T,Option<Tuple2<? extends U,? extends T>>> f)
None when it's
done generating elements, otherwise Some Tuple
of the element for the next call and the value to add to the
resulting iterator.
Example:
Iterator.unfoldRight(10, x -> x == 0
? Option.none()
: Option.of(new Tuple2<>(x, x-1)));
// List(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 iterationjava.lang.NullPointerException - if f is nulldefault Iterator<T> distinct()
Traversableequals.distinct in interface Traversable<T>Traversable containing this elements without duplicatesdefault Iterator<T> distinctBy(java.util.Comparator<? super T> comparator)
Traversablecomparator.distinctBy in interface Traversable<T>comparator - A comparatorTraversable containing this elements without duplicatesdefault <U> Iterator<T> distinctBy(java.util.function.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 Traversable<T>U - key typekeyExtractor - A key extractorTraversable containing this elements without duplicatesdefault Iterator<T> drop(int n)
drop in interface Traversable<T>n - A numbern <= 0 or this is empty, otherwise a new iterator without the first n elements.default Iterator<T> dropRight(int n)
TraversabledropRight in interface Traversable<T>n - The number of elements to drop.default Iterator<T> dropUntil(java.util.function.Predicate<? super T> predicate)
TraversabledropUntil in interface Traversable<T>predicate - A condition tested subsequently for this elements.default Iterator<T> dropWhile(java.util.function.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 Traversable<T>predicate - A condition tested subsequently for this elements.default Iterator<T> filter(java.util.function.Predicate<? super T> predicate)
predicate.filter in interface Traversable<T>predicate - A predicatedefault Iterator<T> filterNot(java.util.function.Predicate<? super T> predicate)
predicate.filterNot in interface Traversable<T>predicate - A predicatedefault Option<T> findLast(java.util.function.Predicate<? super T> predicate)
Traversable
Same as reverse().find(predicate).
findLast in interface Traversable<T>predicate - A predicate.List.of(null).find(e -> e == null)).default <U> Iterator<U> flatMap(java.util.function.Function<? super T,? extends java.lang.Iterable<? extends U>> mapper)
flatMap in interface Traversable<T>U - Component type of the resulting Iteratormapper - A mapperdefault <U> U foldRight(U zero,
java.util.function.BiFunction<? super T,? super U,? extends U> f)
Traversablezero and successively calling combine.
Example:
// = "!cba"
List("a", "b", "c").foldRight("!", (x, xs) -> xs + x)
default T get()
TraversableTraversable is not empty, otherwise throws.default <C> Map<C,Iterator<T>> groupBy(java.util.function.Function<? super T,? extends C> classifier)
TraversablegroupBy in interface Traversable<T>C - classified class typeclassifier - A function which classifies elements into classesTraversable.arrangeBy(Function)default Iterator<Seq<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).grouped in interface Traversable<T>size - a positive block sizedefault boolean hasDefiniteSize()
TraversableThis method should be implemented by classes only, i.e. not by interfaces.
hasDefiniteSize in interface Traversable<T>default T head()
Traversablehead in interface Traversable<T>default Iterator<T> init()
Traversableinit in interface Traversable<T>default Option<Iterator<T>> initOption()
TraversableOption.initOption in interface Traversable<T>Some(traversable) or None if this is empty.default boolean isAsync()
Iterator is computed synchronously.default boolean isEmpty()
Traversabledefault boolean isLazy()
Iterator 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 boolean isSequential()
TraversableisSequential in interface Traversable<T>default Iterator<T> iterator()
Traversabledefault T last()
Traversablelast in interface Traversable<T>default int length()
Traversable
Same as Traversable.size().
length in interface Traversable<T>default <U> Iterator<U> map(java.util.function.Function<? super T,? extends U> mapper)
mapper.default Option<T> nextOption()
Iterator.next() that is equivalent to
hasNext() ? Option.some(next()) : Option.none()
Optiondefault Iterator<T> orElse(java.lang.Iterable<? extends T> other)
TraversableTraversable if it is nonempty, otherwise return the alternative.orElse in interface Traversable<T>other - An alternative TraversableTraversable if it is nonempty, otherwise return the alternative.default Iterator<T> orElse(java.util.function.Supplier<? extends java.lang.Iterable<? extends T>> supplier)
TraversableTraversable if it is nonempty, otherwise return the result of evaluating supplier.orElse in interface Traversable<T>supplier - An alternative Traversable supplierTraversable if it is nonempty, otherwise return the result of evaluating supplier.default Tuple2<Iterator<T>,Iterator<T>> partition(java.util.function.Predicate<? super T> predicate)
TraversableTraversable by splitting this elements in two in distinct traversables
according to a predicate.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 Iterator<T> peek(java.util.function.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 T reduceLeft(java.util.function.BiFunction<? super T,? super T,? extends T> op)
Traversableop from the left.reduceLeft in interface Foldable<T>reduceLeft in interface Traversable<T>op - A BiFunction of type Tdefault T reduceRight(java.util.function.BiFunction<? super T,? super T,? extends T> op)
Traversableop from the right.reduceRight in interface Foldable<T>reduceRight in interface Traversable<T>op - An operation of type Tdefault Iterator<T> replace(T currentElement, T newElement)
Traversablereplace in interface Traversable<T>currentElement - An element to be substituted.newElement - A replacement for currentElement.default Iterator<T> replaceAll(T currentElement, T newElement)
TraversablereplaceAll in interface Traversable<T>currentElement - An element to be substituted.newElement - A replacement for currentElement.default Iterator<T> retainAll(java.lang.Iterable<? extends T> elements)
TraversableretainAll in interface Traversable<T>elements - Elements to be kept.default Traversable<T> scan(T zero, java.util.function.BiFunction<? super T,? super T,? extends T> operation)
Traversablescan in interface Traversable<T>zero - neutral element for the operator opoperation - the associative operator for the scandefault <U> Iterator<U> scanLeft(U zero, java.util.function.BiFunction<? super U,? super T,? extends U> operation)
TraversablescanLeft 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> Iterator<U> scanRight(U zero, java.util.function.BiFunction<? super T,? super U,? extends U> operation)
TraversablescanRight 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 Iterator<Seq<T>> slideBy(java.util.function.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]]
slideBy in interface Traversable<T>classifier - A function which classifies elements into classesdefault Iterator<Seq<T>> sliding(int size)
Traversablesize and step size 1 over this Traversable by calling
Traversable.sliding(int, int).sliding in interface Traversable<T>size - a positive window sizedefault Iterator<Seq<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]]
sliding in interface Traversable<T>size - a positive window sizestep - a positive step sizedefault Tuple2<Iterator<T>,Iterator<T>> span(java.util.function.Predicate<? super T> predicate)
Traversablepredicate and the second element is the remainder.span in interface Traversable<T>predicate - A predicate.Tuple containing the longest prefix of elements that satisfy p and the remainder.default java.lang.String stringPrefix()
ValuestringPrefix in interface Value<T>default Iterator<T> tail()
Traversabletail in interface Traversable<T>default Option<Iterator<T>> tailOption()
TraversableOption.tailOption in interface Traversable<T>Some(traversable) or None if this is empty.default Iterator<T> take(int n)
take in interface Traversable<T>n - A numbern <= 0 or this is empty, otherwise a new iterator without the first n elements.default Iterator<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 Traversable<T>n - The number of elements to take.default Iterator<T> takeUntil(java.util.function.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 Traversable<T>predicate - A condition tested subsequently for this elements.default Iterator<T> takeWhile(java.util.function.Predicate<? super T> predicate)
TraversabletakeWhile in interface Traversable<T>predicate - A condition tested subsequently for the contained elements.