Added in API level 24

IntStream

interface IntStream : BaseStream<Int!, IntStream!>

java.util.stream.IntStream

A sequence of primitive int-valued elements supporting sequential and parallel aggregate operations. This is the int primitive specialization of .

The following example illustrates an aggregate operation using Stream and IntStream, computing the sum of the weights of the red widgets:

<code>int sum = widgets.stream()
                       .filter(w -&gt; w.getColor() == RED)
                       .mapToInt(w -&gt; w.getWeight())
                       .sum();
  </code>

See the class documentation for Stream and the package documentation for java.util.stream for additional specification of streams, stream operations, stream pipelines, and parallelism.

Summary

Nested classes
abstract	`Builder` A mutable builder for an `IntStream`.
abstract	`IntMapMultiConsumer` Represents an operation that accepts an `int`-valued argument and an IntConsumer, and returns no result.

Public methods
abstract Boolean	`allMatch(predicate: IntPredicate!)` Returns whether all elements of this stream match the provided predicate.
abstract Boolean	`anyMatch(predicate: IntPredicate!)` Returns whether any elements of this stream match the provided predicate.
abstract DoubleStream!	`asDoubleStream()` Returns a `DoubleStream` consisting of the elements of this stream, converted to `double`.
abstract LongStream!	`asLongStream()` Returns a `LongStream` consisting of the elements of this stream, converted to `long`.
abstract OptionalDouble!	`average()` Returns an `OptionalDouble` describing the arithmetic mean of elements of this stream, or an empty optional if this stream is empty.
abstract Stream<Int!>!	`boxed()` Returns a `Stream` consisting of the elements of this stream, each boxed to an `Integer`.
open static IntStream.Builder!	`builder()` Returns a builder for an `IntStream`.
abstract R	`collect(supplier: Supplier<R>!, accumulator: ObjIntConsumer<R>!, combiner: BiConsumer<R, R>!)` Performs a mutable reduction operation on the elements of this stream.
open static IntStream!	`concat(a: IntStream!, b: IntStream!)` Creates a lazily concatenated stream whose elements are all the elements of the first stream followed by all the elements of the second stream.
abstract Long	`count()` Returns the count of elements in this stream.
abstract IntStream!	`distinct()` Returns a stream consisting of the distinct elements of this stream.
open IntStream!	`dropWhile(predicate: IntPredicate!)` Returns, if this stream is ordered, a stream consisting of the remaining elements of this stream after dropping the longest prefix of elements that match the given predicate.
open static IntStream!	`empty()` Returns an empty sequential `IntStream`.
abstract IntStream!	`filter(predicate: IntPredicate!)` Returns a stream consisting of the elements of this stream that match the given predicate.
abstract OptionalInt!	`findAny()` Returns an `OptionalInt` describing some element of the stream, or an empty `OptionalInt` if the stream is empty.
abstract OptionalInt!	`findFirst()` Returns an `OptionalInt` describing the first element of this stream, or an empty `OptionalInt` if the stream is empty.
abstract IntStream!	`flatMap(mapper: IntFunction<out IntStream!>!)` Returns a stream consisting of the results of replacing each element of this stream with the contents of a mapped stream produced by applying the provided mapping function to each element.
abstract Unit	`forEach(action: IntConsumer!)` Performs an action for each element of this stream.
abstract Unit	`forEachOrdered(action: IntConsumer!)` Performs an action for each element of this stream, guaranteeing that each element is processed in encounter order for streams that have a defined encounter order.
open static IntStream!	`generate(s: IntSupplier!)` Returns an infinite sequential unordered stream where each element is generated by the provided `IntSupplier`.
open static IntStream!	`iterate(seed: Int, hasNext: IntPredicate!, next: IntUnaryOperator!)` Returns a sequential ordered `IntStream` produced by iterative application of the given `next` function to an initial element, conditioned on satisfying the given `hasNext` predicate.
open static IntStream!	`iterate(seed: Int, f: IntUnaryOperator!)` Returns an infinite sequential ordered `IntStream` produced by iterative application of a function `f` to an initial element `seed`, producing a `Stream` consisting of `seed`, `f(seed)`, `f(f(seed))`, etc.
abstract PrimitiveIterator.OfInt!	`iterator()` Returns an iterator for the elements of this stream.
abstract IntStream!	`limit(maxSize: Long)` Returns a stream consisting of the elements of this stream, truncated to be no longer than `maxSize` in length.
abstract IntStream!	`map(mapper: IntUnaryOperator!)` Returns a stream consisting of the results of applying the given function to the elements of this stream.
open IntStream!	`mapMulti(mapper: IntStream.IntMapMultiConsumer!)` Returns a stream consisting of the results of replacing each element of this stream with multiple elements, specifically zero or more elements.
abstract DoubleStream!	`mapToDouble(mapper: IntToDoubleFunction!)` Returns a `DoubleStream` consisting of the results of applying the given function to the elements of this stream.
abstract LongStream!	`mapToLong(mapper: IntToLongFunction!)` Returns a `LongStream` consisting of the results of applying the given function to the elements of this stream.
abstract Stream<U>!	`mapToObj(mapper: IntFunction<out U>!)` Returns an object-valued `Stream` consisting of the results of applying the given function to the elements of this stream.
abstract OptionalInt!	`max()` Returns an `OptionalInt` describing the maximum element of this stream, or an empty optional if this stream is empty.
abstract OptionalInt!	`min()` Returns an `OptionalInt` describing the minimum element of this stream, or an empty optional if this stream is empty.
abstract Boolean	`noneMatch(predicate: IntPredicate!)` Returns whether no elements of this stream match the provided predicate.
open static IntStream!	`of(t: Int)` Returns a sequential `IntStream` containing a single element.
open static IntStream!	`of(vararg values: Int)` Returns a sequential ordered stream whose elements are the specified values.
abstract IntStream!	`parallel()` Returns an equivalent stream that is parallel.
abstract IntStream!	`peek(action: IntConsumer!)` Returns a stream consisting of the elements of this stream, additionally performing the provided action on each element as elements are consumed from the resulting stream.
open static IntStream!	`range(startInclusive: Int, endExclusive: Int)` Returns a sequential ordered `IntStream` from `startInclusive` (inclusive) to `endExclusive` (exclusive) by an incremental step of `1`.
open static IntStream!	`rangeClosed(startInclusive: Int, endInclusive: Int)` Returns a sequential ordered `IntStream` from `startInclusive` (inclusive) to `endInclusive` (inclusive) by an incremental step of `1`.
abstract Int	`reduce(identity: Int, op: IntBinaryOperator!)` Performs a reduction on the elements of this stream, using the provided identity value and an associative accumulation function, and returns the reduced value.
abstract OptionalInt!	`reduce(op: IntBinaryOperator!)` Performs a reduction on the elements of this stream, using an associative accumulation function, and returns an `OptionalInt` describing the reduced value, if any.
abstract IntStream!	`sequential()` Returns an equivalent stream that is sequential.
abstract IntStream!	`skip(n: Long)` Returns a stream consisting of the remaining elements of this stream after discarding the first `n` elements of the stream.
abstract IntStream!	`sorted()` Returns a stream consisting of the elements of this stream in sorted order.
abstract Spliterator.OfInt!	`spliterator()` Returns a spliterator for the elements of this stream.
abstract Int	`sum()` Returns the sum of elements in this stream.
abstract IntSummaryStatistics!	`summaryStatistics()` Returns an `IntSummaryStatistics` describing various summary data about the elements of this stream.
open IntStream!	`takeWhile(predicate: IntPredicate!)` Returns, if this stream is ordered, a stream consisting of the longest prefix of elements taken from this stream that match the given predicate.
abstract IntArray!	`toArray()` Returns an array containing the elements of this stream.

Inherited functions

From class BaseStream

`Unit`	`close()` Closes this stream, causing all close handlers for this stream pipeline to be called.
`Boolean`	`isParallel()` Returns whether this stream, if a terminal operation were to be executed, would execute in parallel. Calling this method after invoking an terminal stream operation method may yield unpredictable results.
`S`	`onClose(closeHandler: Runnable!)` Returns an equivalent stream with an additional close handler. Close handlers are run when the `close()` method is called on the stream, and are executed in the order they were added. All close handlers are run, even if earlier close handlers throw exceptions. If any close handler throws an exception, the first exception thrown will be relayed to the caller of `close()`, with any remaining exceptions added to that exception as suppressed exceptions (unless one of the remaining exceptions is the same exception as the first exception, since an exception cannot suppress itself.) May return itself. This is an intermediate operation.
`S`	`unordered()` Returns an equivalent stream that is unordered. May return itself, either because the stream was already unordered, or because the underlying stream state was modified to be unordered. This is an intermediate operation.

Public methods

allMatch

Added in API level 24

abstract fun allMatch(predicate: IntPredicate!): Boolean

Returns whether all elements of this stream match the provided predicate. May not evaluate the predicate on all elements if not necessary for determining the result. If the stream is empty then true is returned and the predicate is not evaluated.

This is a short-circuiting terminal operation.

Parameters
`predicate`	IntPredicate!: a non-interfering, stateless predicate to apply to elements of this stream

Return
`Boolean`	`true` if either all elements of the stream match the provided predicate or the stream is empty, otherwise `false`

anyMatch

Added in API level 24

abstract fun anyMatch(predicate: IntPredicate!): Boolean

Returns whether any elements of this stream match the provided predicate. May not evaluate the predicate on all elements if not necessary for determining the result. If the stream is empty then false is returned and the predicate is not evaluated.

This is a short-circuiting terminal operation.

Parameters
`predicate`	IntPredicate!: a non-interfering, stateless predicate to apply to elements of this stream

Return
`Boolean`	`true` if any elements of the stream match the provided predicate, otherwise `false`

asDoubleStream

Added in API level 24

abstract fun asDoubleStream(): DoubleStream!

Returns a DoubleStream consisting of the elements of this stream, converted to double.

This is an intermediate operation.

Return
`DoubleStream!`	a `DoubleStream` consisting of the elements of this stream, converted to `double`

asLongStream

Added in API level 24

abstract fun asLongStream(): LongStream!

Returns a LongStream consisting of the elements of this stream, converted to long.

This is an intermediate operation.

Return
`LongStream!`	a `LongStream` consisting of the elements of this stream, converted to `long`

average

Added in API level 24

abstract fun average(): OptionalDouble!

Returns an OptionalDouble describing the arithmetic mean of elements of this stream, or an empty optional if this stream is empty. This is a special case of a reduction.

This is a terminal operation.

Return
`OptionalDouble!`	an `OptionalDouble` containing the average element of this stream, or an empty optional if the stream is empty

boxed

Added in API level 24

abstract fun boxed(): Stream<Int!>!

Returns a Stream consisting of the elements of this stream, each boxed to an Integer.

This is an intermediate operation.

Return
`Stream<Int!>!`	a `Stream` consistent of the elements of this stream, each boxed to an `Integer`

builder

Added in API level 24

open static fun builder(): IntStream.Builder!

Returns a builder for an IntStream.

Return
`IntStream.Builder!`	a stream builder

collect

Added in API level 24

abstract fun <R : Any!> collect(
    supplier: Supplier<R>!, 
    accumulator: ObjIntConsumer<R>!, 
    combiner: BiConsumer<R, R>!
): R

Performs a mutable reduction operation on the elements of this stream. A mutable reduction is one in which the reduced value is a mutable result container, such as an ArrayList, and elements are incorporated by updating the state of the result rather than by replacing the result. This produces a result equivalent to:

<code>R result = supplier.get();
      for (int element : this stream)
          accumulator.accept(result, element);
      return result;
  </code>

Like reduce(int,IntBinaryOperator), collect operations can be parallelized without requiring additional synchronization.

This is a terminal operation.

Parameters
`<R>`	the type of the mutable result container
`supplier`	Supplier<R>!: a function that creates a new mutable result container. For a parallel execution, this function may be called multiple times and must return a fresh value each time.
`accumulator`	ObjIntConsumer<R>!: an associative, non-interfering, stateless function that must fold an element into a result container.
`combiner`	BiConsumer<R, R>!: an associative, non-interfering, stateless function that accepts two partial result containers and merges them, which must be compatible with the accumulator function. The combiner function must fold the elements from the second result container into the first result container.

Return
`R`	the result of the reduction

See Also

java.util.stream.Stream#collect(java.util.function.Supplier,java.util.function.BiConsumer,java.util.function.BiConsumer)

concat

Added in API level 24

open static fun concat(
    a: IntStream!, 
    b: IntStream!
): IntStream!

Creates a lazily concatenated stream whose elements are all the elements of the first stream followed by all the elements of the second stream. The resulting stream is ordered if both of the input streams are ordered, and parallel if either of the input streams is parallel. When the resulting stream is closed, the close handlers for both input streams are invoked.

This method operates on the two input streams and binds each stream to its source. As a result subsequent modifications to an input stream source may not be reflected in the concatenated stream result.

Parameters
`a`	IntStream!: the first stream
`b`	IntStream!: the second stream

Return
`IntStream!`	the concatenation of the two input streams

count

Added in API level 24

abstract fun count(): Long

Returns the count of elements in this stream. This is a special case of a reduction and is equivalent to:

<code>return mapToLong(e -&gt; 1L).sum();
  </code>

This is a terminal operation.

Return
`Long`	the count of elements in this stream

distinct

Added in API level 24

abstract fun distinct(): IntStream!

Returns a stream consisting of the distinct elements of this stream.

This is a stateful intermediate operation.

Return
`IntStream!`	the new stream

dropWhile

Added in API level 35

open fun dropWhile(predicate: IntPredicate!): IntStream!

Returns, if this stream is ordered, a stream consisting of the remaining elements of this stream after dropping the longest prefix of elements that match the given predicate. Otherwise returns, if this stream is unordered, a stream consisting of the remaining elements of this stream after dropping a subset of elements that match the given predicate.

If this stream is ordered then the longest prefix is a contiguous sequence of elements of this stream that match the given predicate. The first element of the sequence is the first element of this stream, and the element immediately following the last element of the sequence does not match the given predicate.

If this stream is unordered, and some (but not all) elements of this stream match the given predicate, then the behavior of this operation is nondeterministic; it is