DoubleStream (Lightweight-Stream-API 1.2.1 API)

java.lang.Object
- com.annimon.stream.DoubleStream

All Implemented Interfaces:

Closeable, AutoCloseable
```
public final class DoubleStream
extends Object
implements Closeable
```
A sequence of double-valued elements supporting aggregate operations.

Since:

1.1.4

See Also:

Stream

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`allMatch(DoublePredicate predicate)` Tests whether all elements match the given predicate.
`boolean`	`anyMatch(DoublePredicate predicate)` Tests whether all elements match the given predicate.
`OptionalDouble`	`average()` Returns the average of elements in this stream.
`Stream<Double>`	`boxed()` Returns a `Stream` consisting of the elements of this stream, each boxed to an `Double`.
`void`	`close()` Causes close handler to be invoked if it exists.
`<R> R`	`collect(Supplier<R> supplier, ObjDoubleConsumer<R> accumulator)` Collects elements to `supplier` provided container by applying the given accumulation function.
`static DoubleStream`	`concat(DoubleStream a, DoubleStream b)` Concatenates two streams.
`long`	`count()` Returns the count of elements in this stream.
`<R> R`	`custom(Function<DoubleStream,R> function)` Applies custom operator on stream.
`DoubleStream`	`distinct()` Returns a stream consisting of the distinct elements of this stream.
`DoubleStream`	`dropWhile(DoublePredicate predicate)` Drops elements while the predicate is true and returns the rest.
`static DoubleStream`	`empty()` Returns an empty stream.
`DoubleStream`	`filter(DoublePredicate predicate)` Returns `DoubleStream` with elements that satisfy the given predicate.
`DoubleStream`	`filterIndexed(IndexedDoublePredicate predicate)` Returns a `DoubleStream` with elements that satisfy the given `IndexedDoublePredicate`.
`DoubleStream`	`filterIndexed(int from, int step, IndexedDoublePredicate predicate)` Returns a `DoubleStream` with elements that satisfy the given `IndexedDoublePredicate`.
`DoubleStream`	`filterNot(DoublePredicate predicate)` Returns `DoubleStream` with elements that does not satisfy the given predicate.
`OptionalDouble`	`findFirst()` Returns the first element wrapped by `OptionalDouble` class.
`OptionalDouble`	`findLast()` Returns the last element wrapped by `OptionalDouble` class.
`OptionalDouble`	`findSingle()` Returns the single element wrapped by `OptionalDouble` class.
`DoubleStream`	`flatMap(DoubleFunction<? extends DoubleStream> mapper)` 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.
`void`	`forEach(DoubleConsumer action)` Performs an action for each element of this stream.
`void`	`forEachIndexed(IndexedDoubleConsumer action)` Performs the given indexed action on each element.
`void`	`forEachIndexed(int from, int step, IndexedDoubleConsumer action)` Performs the given indexed action on each element.
`static DoubleStream`	`generate(DoubleSupplier s)` Creates a `DoubleStream` by elements that generated by `DoubleSupplier`.
`static DoubleStream`	`iterate(double seed, DoublePredicate predicate, DoubleUnaryOperator op)` Creates an `DoubleStream` by iterative application `DoubleUnaryOperator` function to an initial element `seed`, conditioned on satisfying the supplied predicate.
`static DoubleStream`	`iterate(double seed, DoubleUnaryOperator f)` Creates a `DoubleStream` by iterative application `DoubleUnaryOperator` function to an initial element `seed`.
`PrimitiveIterator.OfDouble`	`iterator()` Returns internal `DoubleStream` iterator.
`DoubleStream`	`limit(long maxSize)` Returns a stream consisting of the elements of this stream, truncated to be no longer than `maxSize` in length.
`DoubleStream`	`map(DoubleUnaryOperator mapper)` Returns an `DoubleStream` consisting of the results of applying the given function to the elements of this stream.
`DoubleStream`	`mapIndexed(IndexedDoubleUnaryOperator mapper)` Returns a `DoubleStream` with elements that obtained by applying the given `IndexedDoubleUnaryOperator`.
`DoubleStream`	`mapIndexed(int from, int step, IndexedDoubleUnaryOperator mapper)` Returns a `DoubleStream` with elements that obtained by applying the given `IndexedDoubleUnaryOperator`.
`IntStream`	`mapToInt(DoubleToIntFunction mapper)` Returns an `IntStream` consisting of the results of applying the given function to the elements of this stream.
`LongStream`	`mapToLong(DoubleToLongFunction mapper)` Returns an `LongStream` consisting of the results of applying the given function to the elements of this stream.
`<R> Stream<R>`	`mapToObj(DoubleFunction<? extends R> mapper)` Returns a `Stream` consisting of the results of applying the given function to the elements of this stream.
`OptionalDouble`	`max()` Returns an `OptionalDouble` describing the maximum element of this stream, or an empty optional if this stream is empty.
`OptionalDouble`	`min()` Returns an `OptionalDouble` describing the minimum element of this stream, or an empty optional if this stream is empty.
`boolean`	`noneMatch(DoublePredicate predicate)` Tests whether no elements match the given predicate.
`static DoubleStream`	`of(double... values)` Creates a `DoubleStream` from the specified values.
`static DoubleStream`	`of(double t)` Returns stream which contains single element passed as param
`static DoubleStream`	`of(PrimitiveIterator.OfDouble iterator)` Creates a `DoubleStream` from `PrimitiveIterator.OfDouble`.
`DoubleStream`	`onClose(Runnable closeHandler)` Adds close handler to the current stream.
`DoubleStream`	`peek(DoubleConsumer action)` Performs provided action on each element.
`OptionalDouble`	`reduce(DoubleBinaryOperator accumulator)` Performs a reduction on the elements of this stream, using an associative accumulation function, and returns an `OptionalDouble` describing the reduced value, if any.
`double`	`reduce(double identity, DoubleBinaryOperator accumulator)` Performs a reduction on the elements of this stream, using the provided identity value and an associative accumulation function, and returns the reduced value.
`DoubleStream`	`sample(int stepWidth)` Samples the `DoubleStream` by emitting every n-th element.
`DoubleStream`	`scan(DoubleBinaryOperator accumulator)` Returns a `DoubleStream` produced by iterative application of a accumulation function to reduction value and next element of the current stream.
`DoubleStream`	`scan(double identity, DoubleBinaryOperator accumulator)` Returns a `DoubleStream` produced by iterative application of a accumulation function to an initial element `identity` and next element of the current stream.
`double`	`single()` Returns the single element of stream.
`DoubleStream`	`skip(long n)` Skips first `n` elements and returns `DoubleStream` with remaining elements.
`DoubleStream`	`sorted()` Returns a stream consisting of the elements of this stream in sorted order.
`DoubleStream`	`sorted(Comparator<Double> comparator)` Returns a stream consisting of the elements of this stream in sorted order as determinated by provided `Comparator`.
`double`	`sum()` Returns the sum of elements in this stream.
`DoubleStream`	`takeUntil(DoublePredicate stopPredicate)` Takes elements while the predicate returns `false`.
`DoubleStream`	`takeWhile(DoublePredicate predicate)` Takes elements while the predicate returns `true`.
`double[]`	`toArray()` Returns an array containing the elements of this stream.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Method Detail
  - empty
```
public static DoubleStream empty()
```
    Returns an empty stream.
    
    Returns:
    
    the empty stream
  - of
```
public static DoubleStream of(PrimitiveIterator.OfDouble iterator)
```
    Creates a DoubleStream from PrimitiveIterator.OfDouble.
    
    Parameters:
    
    iterator - the iterator with elements to be passed to stream
    
    Returns:
    
    the new DoubleStream
    
    Throws:
    
    NullPointerException - if iterator is null
  - of
```
public static DoubleStream of(double... values)
```
    Creates a DoubleStream from the specified values.
    
    Parameters:
    
    values - the elements of the new stream
    
    Returns:
    
    the new stream
    
    Throws:
    
    NullPointerException - if values is null
  - of
```
public static DoubleStream of(double t)
```
    Returns stream which contains single element passed as param
    
    Parameters:
    
    t - element of the stream
    
    Returns:
    
    the new stream
  - generate
```
public static DoubleStream generate(DoubleSupplier s)
```
    Creates a DoubleStream by elements that generated by DoubleSupplier.
    
    Parameters:
    
    s - the DoubleSupplier for generated elements
    
    Returns:
    
    a new infinite sequential DoubleStream
    
    Throws:
    
    NullPointerException - if s is null
  - iterate
```
public static DoubleStream iterate(double seed,
                                   DoubleUnaryOperator f)
```
    Creates a DoubleStream by iterative application DoubleUnaryOperator function to an initial element seed. Produces DoubleStream consisting of seed, f(seed), f(f(seed)), etc.
    The first element (position 0) in the DoubleStream will be the provided seed. For n > 0, the element at position n, will be the result of applying the function f to the element at position n - 1.
    Example:
```
 seed: 1
 f: (a) -> a + 5
 result: [1, 6, 11, 16, ...]
 
```
    Parameters:
    
    seed - the initial element
    
    f - a function to be applied to the previous element to produce a new element
    
    Returns:
    
    a new sequential DoubleStream
    
    Throws:
    
    NullPointerException - if f is null
  - iterate
```
public static DoubleStream iterate(double seed,
                                   DoublePredicate predicate,
                                   DoubleUnaryOperator op)
```
    Creates an DoubleStream by iterative application DoubleUnaryOperator function to an initial element seed, conditioned on satisfying the supplied predicate.
    Example:
```
 seed: 0.0
 predicate: (a) -> a < 0.2
 f: (a) -> a + 0.05
 result: [0.0, 0.05, 0.1, 0.15]
 
```
    Parameters:
    
    seed - the initial value
    
    predicate - a predicate to determine when the stream must terminate
    
    op - operator to produce new element by previous one
    
    Returns:
    
    the new stream
    
    Throws:
    
    NullPointerException - if op is null
    
    Since:
    
    1.1.5
  - concat
```
public static DoubleStream concat(DoubleStream a,
                                  DoubleStream b)
```
    Concatenates two streams.
    Example:
```
 stream a: [1, 2, 3, 4]
 stream b: [5, 6]
 result:   [1, 2, 3, 4, 5, 6]
 
```
    Parameters:
    
    a - the first stream
    
    b - the second stream
    
    Returns:
    
    the new concatenated stream
    
    Throws:
    
    NullPointerException - if a or b is null
  - iterator
```
public PrimitiveIterator.OfDouble iterator()
```
    Returns internal DoubleStream iterator.
    
    Returns:
    
    internal DoubleStream iterator.
  - custom
```
public <R> R custom(Function<DoubleStream,R> function)
```
    Applies custom operator on stream. Transforming function can return DoubleStream for intermediate operations, or any value for terminal operation.
    Operator examples:
```
     // Intermediate operator
     public class Zip implements Function<DoubleStream, DoubleStream> {

         private final DoubleStream secondStream;
         private final DoubleBinaryOperator combiner;

         public Zip(DoubleStream secondStream, DoubleBinaryOperator combiner) {
             this.secondStream = secondStream;
             this.combiner = combiner;
         }

         @Override
         public DoubleStream apply(DoubleStream firstStream) {
             final PrimitiveIterator.OfDouble it1 = firstStream.iterator();
             final PrimitiveIterator.OfDouble it2 = secondStream.iterator();
             return DoubleStream.of(new PrimitiveIterator.OfDouble() {
                 @Override
                 public boolean hasNext() {
                     return it1.hasNext() && it2.hasNext();
                 }

                 @Override
                 public double nextDouble() {
                     return combiner.applyAsDouble(it1.nextDouble(), it2.nextDouble());
                 }
             });
         }
     }

     // Intermediate operator based on existing stream operators
     public class SkipAndLimit implements UnaryOperator<DoubleStream> {

         private final int skip, limit;

         public SkipAndLimit(int skip, int limit) {
             this.skip = skip;
             this.limit = limit;
         }

         @Override
         public DoubleStream apply(DoubleStream stream) {
             return stream.skip(skip).limit(limit);
         }
     }

     // Terminal operator
     public class DoubleSummaryStatistics implements Function<DoubleStream, double[]> {
         @Override
         public double[] apply(DoubleStream stream) {
             long count = 0;
             double sum = 0;
             final PrimitiveIterator.OfDouble it = stream.iterator();
             while (it.hasNext()) {
                 count++;
                 sum += it.nextDouble();
             }
             double average = (count == 0) ? 0 : (sum / (double) count);
             return new double[] {count, sum, average};
         }
     }
 
```
    Type Parameters:
    
    R - the type of the result
    
    Parameters:
    
    function - a transforming function
    
    Returns:
    
    a result of the transforming function
    
    Throws:
    
    NullPointerException - if function is null
    
    See Also:
    
    Stream.custom(com.annimon.stream.function.Function)
  - boxed
```
public Stream<Double> boxed()
```
    Returns a Stream consisting of the elements of this stream, each boxed to an Double.
    This is an lazy intermediate operation.
    
    Returns:
    
    a Stream consistent of the elements of this stream, each boxed to an Double
  - filter
```
public DoubleStream filter(DoublePredicate predicate)
```
    Returns DoubleStream with elements that satisfy the given predicate.
    This is an intermediate operation.
    Example:
```
 predicate: (a) -> a > 2
 stream: [1, 2, 3, 4, -8, 0, 11]
 result: [3, 4, 11]
 
```
    Parameters:
    
    predicate - the predicate used to filter elements
    
    Returns:
    
    the new stream
  - filterIndexed
```
public DoubleStream filterIndexed(IndexedDoublePredicate predicate)
```
    Returns a DoubleStream with elements that satisfy the given IndexedDoublePredicate.
    This is an intermediate operation.
    Example:
```
 predicate: (index, value) -> (index + value) > 6
 stream: [1, 2, 3, 4, 0, 11]
 index:  [0, 1, 2, 3, 4,  5]
 sum:    [1, 3, 5, 7, 4, 16]
 filter: [         7,    16]
 result: [4, 11]
 
```
    Parameters:
    
    predicate - the IndexedDoublePredicate used to filter elements
    
    Returns:
    
    the new stream
    
    Since:
    
    1.2.1
  - filterIndexed
```
public DoubleStream filterIndexed(int from,
                                  int step,
                                  IndexedDoublePredicate predicate)
```
    Returns a DoubleStream with elements that satisfy the given IndexedDoublePredicate.
    This is an intermediate operation.
    Example:
```
 from: 4
 step: 3
 predicate: (index, value) -> (index + value) > 15
 stream: [1, 2,  3,  4,  0, 11]
 index:  [4, 7, 10, 13, 16, 19]
 sum:    [5, 9, 13, 17, 16, 30]
 filter: [          17, 16, 30]
 result: [4, 0, 11]
 
```
    Parameters:
    
    from - the initial value of the index (inclusive)
    
    step - the step of the index
    
    predicate - the IndexedDoublePredicate used to filter elements
    
    Returns:
    
    the new stream
    
    Since:
    
    1.2.1
  - filterNot
```
public DoubleStream filterNot(DoublePredicate predicate)
```
    Returns DoubleStream with elements that does not satisfy the given predicate.
    This is an intermediate operation.
    
    Parameters:
    
    predicate - the predicate used to filter elements
    
    Returns:
    
    the new stream
  - map
```
public DoubleStream map(DoubleUnaryOperator mapper)
```
    Returns an DoubleStream consisting of the results of applying the given function to the elements of this stream.
    This is an intermediate operation.
    Example:
```
 mapper: (a) -> a + 5
 stream: [1, 2, 3, 4]
 result: [6, 7, 8, 9]
 
```
    Parameters:
    
    mapper - the mapper function used to apply to each element
    
    Returns:
    
    the new stream
    
    See Also:
    
    Stream.map(com.annimon.stream.function.Function)
  - mapIndexed
```
public DoubleStream mapIndexed(IndexedDoubleUnaryOperator mapper)
```
    Returns a DoubleStream with elements that obtained by applying the given IndexedDoubleUnaryOperator.
    This is an intermediate operation.
    Example:
```
 mapper: (index, value) -> (index * value)
 stream: [1, 2, 3,  4]
 index:  [0, 1, 2,  3]
 result: [0, 2, 6, 12]
 
```
    Parameters:
    
    mapper - the mapper function used to apply to each element
    
    Returns:
    
    the new stream
    
    Since:
    
    1.2.1
  - mapIndexed
```
public DoubleStream mapIndexed(int from,
                               int step,
                               IndexedDoubleUnaryOperator mapper)
```
    Returns a DoubleStream with elements that obtained by applying the given IndexedDoubleUnaryOperator.
    This is an intermediate operation.
    Example:
```
 from: -2
 step: 2
 mapper: (index, value) -> (index * value)
 stream: [ 1, 2, 3,  4]
 index:  [-2, 0, 2,  4]
 result: [-2, 0, 6, 16]
 
```
    Parameters:
    
    from - the initial value of the index (inclusive)
    
    step - the step of the index
    
    mapper - the mapper function used to apply to each element
    
    Returns:
    
    the new stream
    
    Since:
    
    1.2.1
  - mapToObj
```
public <R> Stream<R> mapToObj(DoubleFunction<? extends R> mapper)
```
    Returns a Stream consisting of the results of applying the given function to the elements of this stream.
    This is an intermediate operation.
    
    Type Parameters:
    
    R - the type result
    
    Parameters:
    
    mapper - the mapper function used to apply to each element
    
    Returns:
    
    the new Stream
  - mapToInt
```
public IntStream mapToInt(DoubleToIntFunction mapper)
```
    Returns an IntStream consisting of the results of applying the given function to the elements of this stream.
    This is an intermediate operation.
    
    Parameters:
    
    mapper - the mapper function used to apply to each element
    
    Returns:
    
    the new IntStream
  - mapToLong
```
public LongStream mapToLong(DoubleToLongFunction mapper)
```
    Returns an LongStream consisting of the results of applying the given function to the elements of this stream.
    This is an intermediate operation.
    
    Parameters:
    
    mapper - the mapper function used to apply to each element
    
    Returns:
    
    the new LongStream
  - flatMap
```
public DoubleStream flatMap(DoubleFunction<? extends DoubleStream> mapper)
```
    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.
    This is an intermediate operation.
    Example:
```
 mapper: (a) -> [a, a + 5]
 stream: [1, 2, 3, 4]
 result: [1, 6, 2, 7, 3, 8, 4, 9]
 
```
    Parameters:
    
    mapper - the mapper function used to apply to each element
    
    Returns:
    
    the new stream
    
    See Also:
    
    Stream.flatMap(com.annimon.stream.function.Function)
  - distinct
```
public DoubleStream distinct()
```
    Returns a stream consisting of the distinct elements of this stream.
    This is a stateful intermediate operation.
    Example:
```
 stream: [1, 4, 2, 3, 3, 4, 1]
 result: [1, 4, 2, 3]
 
```
    Returns:
    
    the new stream
  - sorted
```
public DoubleStream sorted()
```
    Returns a stream consisting of the elements of this stream in sorted order.
    This is a stateful intermediate operation.
    Example:
```
 stream: [3, 4, 1, 2]
 result: [1, 2, 3, 4]
 
```
    Returns:
    
    the new stream
  - sorted
```
public DoubleStream sorted(Comparator<Double> comparator)
```
    Returns a stream consisting of the elements of this stream in sorted order as determinated by provided Comparator.
    This is a stateful intermediate operation.
    Example:
```
 comparator: (a, b) -> -a.compareTo(b)
 stream: [1, 2, 3, 4]
 result: [4, 3, 2, 1]
 
```
    Parameters:
    
    comparator - the Comparator to compare elements
    
    Returns:
    
    the new DoubleStream
  - sample
```
public DoubleStream sample(int stepWidth)
```
    Samples the DoubleStream by emitting every n-th element.
    This is an intermediate operation.
    Example:
```
 stepWidth: 3
 stream: [1, 2, 3, 4, 5, 6, 7, 8]
 result: [1, 4, 7]
 
```
    Parameters:
    
    stepWidth - step width
    
    Returns:
    
    the new DoubleStream
    
    Throws:
    
    IllegalArgumentException - if stepWidth is zero or negative
    
    See Also:
    
    Stream.sample(int)
  - peek
```
public DoubleStream peek(DoubleConsumer action)
```
    Performs provided action on each element.
    This is an intermediate operation.
    
    Parameters:
    
    action - the action to be performed on each element
    
    Returns:
    
    the new stream
  - scan
```
public DoubleStream scan(DoubleBinaryOperator accumulator)
```
    Returns a DoubleStream produced by iterative application of a accumulation function to reduction value and next element of the current stream. Produces a DoubleStream consisting of value1, acc(value1, value2), acc(acc(value1, value2), value3), etc.
    This is an intermediate operation.
    Example:
```
 accumulator: (a, b) -> a + b
 stream: [1, 2, 3, 4, 5]
 result: [1, 3, 6, 10, 15]
 
```
    Parameters:
    
    accumulator - the accumulation function
    
    Returns:
    
    the new stream
    
    Throws:
    
    NullPointerException - if accumulator is null
    
    Since:
    
    1.1.6
  - scan
```
public DoubleStream scan(double identity,
                         DoubleBinaryOperator accumulator)
```
    Returns a DoubleStream produced by iterative application of a accumulation function to an initial element identity and next element of the current stream. Produces a DoubleStream consisting of identity, acc(identity, value1), acc(acc(identity, value1), value2), etc.
    This is an intermediate operation.
    Example:
```
 identity: 0
 accumulator: (a, b) -> a + b
 stream: [1, 2, 3, 4, 5]
 result: [0, 1, 3, 6, 10, 15]
 
```
    Parameters:
    
    identity - the initial value
    
    accumulator - the accumulation function
    
    Returns:
    
    the new stream
    
    Throws:
    
    NullPointerException - if accumulator is null
    
    Since:
    
    1.1.6
  - takeWhile
```
public DoubleStream takeWhile(DoublePredicate predicate)
```
    Takes elements while the predicate returns true.
    This is an intermediate operation.
    Example:
```
 predicate: (a) -> a < 3
 stream: [1, 2, 3, 4, 1, 2, 3, 4]
 result: [1, 2]
 
```
    Parameters:
    
    predicate - the predicate used to take elements
    
    Returns:
    
    the new DoubleStream
  - takeUntil
```
public DoubleStream takeUntil(DoublePredicate stopPredicate)
```
    Takes elements while the predicate returns false. Once predicate condition is satisfied by an element, the stream finishes with this element.
    This is an intermediate operation.
    Example:
```
 stopPredicate: (a) -> a > 2
 stream: [1, 2, 3, 4, 1, 2, 3, 4]
 result: [1, 2, 3]
 
```
    Parameters:
    
    stopPredicate - the predicate used to take elements
    
    Returns:
    
    the new DoubleStream
    
    Since:
    
    1.1.6
  - dropWhile
```
public DoubleStream dropWhile(DoublePredicate predicate)
```
    Drops elements while the predicate is true and returns the rest.
    This is an intermediate operation.
    Example:
```
 predicate: (a) -> a < 3
 stream: [1, 2, 3, 4, 1, 2, 3, 4]
 result: [3, 4, 1, 2, 3, 4]
 
```
    Parameters:
    
    predicate - the predicate used to drop elements
    
    Returns:
    
    the new DoubleStream
  - limit
```
public DoubleStream limit(long maxSize)
```
    Returns a stream consisting of the elements of this stream, truncated to be no longer than maxSize in length.
    This is a short-circuiting stateful intermediate operation.
    Example:
```
 maxSize: 3
 stream: [1, 2, 3, 4, 5]
 result: [1, 2, 3]

 maxSize: 10
 stream: [1, 2]
 result: [1, 2]
 
```
    Parameters:
    
    maxSize - the number of elements the stream should be limited to
    
    Returns:
    
    the new stream
    
    Throws:
    
    IllegalArgumentException - if maxSize is negative
  - skip
```
public DoubleStream skip(long n)
```
    Skips first n elements and returns DoubleStream with remaining elements. If this stream contains fewer than n elements, then an empty stream will be returned.
    This is a stateful intermediate operation.
    Example:
```
 n: 3
 stream: [1, 2, 3, 4, 5]
 result: [4, 5]

 n: 10
 stream: [1, 2]
 result: []
 
```
    Parameters:
    
    n - the number of elements to skip
    
    Returns:
    
    the new stream
    
    Throws:
    
    IllegalArgumentException - if n is negative
  - forEach
```
public void forEach(DoubleConsumer action)
```
    Performs an action for each element of this stream.
    This is a terminal operation.
    
    Parameters:
    
    action - the action to be performed on each element
  - forEachIndexed
```
public void forEachIndexed(IndexedDoubleConsumer action)
```
    Performs the given indexed action on each element.
    This is a terminal operation.
    
    Parameters:
    
    action - the action to be performed on each element
    
    Since:
    
    1.2.1
  - forEachIndexed
```
public void forEachIndexed(int from,
                           int step,
                           IndexedDoubleConsumer action)
```
    Performs the given indexed action on each element.
    This is a terminal operation.
    
    Parameters:
    
    from - the initial value of the index (inclusive)
    
    step - the step of the index
    
    action - the action to be performed on each element
    
    Since:
    
    1.2.1
  - reduce
```
public double reduce(double identity,
                     DoubleBinaryOperator accumulator)
```
    Performs a reduction on the elements of this stream, using the provided identity value and an associative accumulation function, and returns the reduced value.
    The identity value must be an identity for the accumulator function. This means that for all x, accumulator.apply(identity, x) is equal to x. The accumulator function must be an associative function.
    This is a terminal operation.
    Example:
```
 identity: 0
 accumulator: (a, b) -> a + b
 stream: [1, 2, 3, 4, 5]
 result: 15
 
```
    Parameters:
    
    identity - the identity value for the accumulating function
    
    accumulator - the accumulation function
    
    Returns:
    
    the result of the reduction
    
    See Also:
    
    sum(), min(), max()
  - reduce
```
public OptionalDouble reduce(DoubleBinaryOperator accumulator)
```
    Performs a reduction on the elements of this stream, using an associative accumulation function, and returns an OptionalDouble describing the reduced value, if any.
    The accumulator function must be an associative function.
    This is a terminal operation.
    
    Parameters:
    
    accumulator - the accumulation function
    
    Returns:
    
    the result of the reduction
    
    See Also:
    
    reduce(com.annimon.stream.function.DoubleBinaryOperator)
  - toArray
```
public double[] toArray()
```
    Returns an array containing the elements of this stream.
    This is a terminal operation.
    
    Returns:
    
    an array containing the elements of this stream
  - collect
```
public <R> R collect(Supplier<R> supplier,
                     ObjDoubleConsumer<R> accumulator)
```
    Collects elements to supplier provided container by applying the given accumulation function.
    This is a terminal operation.
    
    Type Parameters:
    
    R - the type of the result
    
    Parameters:
    
    supplier - the supplier function that provides container
    
    accumulator - the accumulation function
    
    Returns:
    
    the result of collect elements
    
    See Also:
    
    Stream.collect(com.annimon.stream.function.Supplier, com.annimon.stream.function.BiConsumer)
  - sum
```
public double sum()
```
    Returns the sum of elements in this stream.
    
    Returns:
    
    the sum of elements in this stream
  - min
```
public OptionalDouble min()
```
    Returns an OptionalDouble describing the minimum element of this stream, or an empty optional if this stream is empty.
    This is a terminal operation.
    
    Returns:
    
    the minimum element
  - max
```
public OptionalDouble max()
```
    Returns an OptionalDouble describing the maximum element of this stream, or an empty optional if this stream is empty.
    This is a terminal operation.
    
    Returns:
    
    the maximum element
  - count
```
public long count()
```
    Returns the count of elements in this stream.
    This is a terminal operation.
    
    Returns:
    
    the count of elements in this stream
  - average
```
public OptionalDouble average()
```
    Returns the average of elements in this stream.
    This is a terminal operation.
    
    Returns:
    
    the average of elements in this stream
  - anyMatch
```
public boolean anyMatch(DoublePredicate predicate)
```
    Tests whether all elements match the given 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.
    Example:
```
 predicate: (a) -> a == 5
 stream: [1, 2, 3, 4, 5]
 result: true

 predicate: (a) -> a == 5
 stream: [5, 5, 5]
 result: true
 
```
    Parameters:
    
    predicate - the predicate used to match elements
    
    Returns:
    
    true if any elements of the stream match the provided predicate, otherwise false
  - allMatch
```
public boolean allMatch(DoublePredicate predicate)
```
    Tests whether all elements match the given 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.
    Example:
```
 predicate: (a) -> a == 5
 stream: [1, 2, 3, 4, 5]
 result: false

 predicate: (a) -> a == 5
 stream: [5, 5, 5]
 result: true
 
```
    Parameters:
    
    predicate - the predicate used to match elements
    
    Returns:
    
    true if either all elements of the stream match the provided predicate or the stream is empty, otherwise false
  - noneMatch
```
public boolean noneMatch(DoublePredicate predicate)
```
    Tests whether no elements match the given 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.
    Example:
```
 predicate: (a) -> a == 5
 stream: [1, 2, 3, 4, 5]
 result: false

 predicate: (a) -> a == 5
 stream: [1, 2, 3]
 result: true
 
```
    Parameters:
    
    predicate - the predicate used to match elements
    
    Returns:
    
    true if either no elements of the stream match the provided predicate or the stream is empty, otherwise false
  - findFirst
```
public OptionalDouble findFirst()
```
    Returns the first element wrapped by OptionalDouble class. If stream is empty, returns OptionalDouble.empty().
    This is a short-circuiting terminal operation.
    
    Returns:
    
    an OptionalDouble with first element or OptionalDouble.empty() if stream is empty
  - findLast
```
public OptionalDouble findLast()
```
    Returns the last element wrapped by OptionalDouble class. If stream is empty, returns OptionalDouble.empty().
    This is a short-circuiting terminal operation.
    
    Returns:
    
    an OptionalDouble with the last element or OptionalDouble.empty() if the stream is empty
    
    Since:
    
    1.1.8
  - single
```
public double single()
```
    Returns the single element of stream. If stream is empty, throws NoSuchElementException. If stream contains more than one element, throws IllegalStateException.
    This is a short-circuiting terminal operation.
    Example:
```
 stream: []
 result: NoSuchElementException

 stream: [1]
 result: 1

 stream: [1, 2, 3]
 result: IllegalStateException
 
```
    Returns:
    
    single element of stream
    
    Throws:
    
    NoSuchElementException - if stream is empty
    
    IllegalStateException - if stream contains more than one element
  - findSingle
```
public OptionalDouble findSingle()
```
    Returns the single element wrapped by OptionalDouble class. If stream is empty, returns OptionalDouble.empty(). If stream contains more than one element, throws IllegalStateException.
    This is a short-circuiting terminal operation.
    Example:
```
 stream: []
 result: OptionalDouble.empty()

 stream: [1]
 result: OptionalDouble.of(1)

 stream: [1, 2, 3]
 result: IllegalStateException
 
```
    Returns:
    
    an OptionalDouble with single element or OptionalDouble.empty() if stream is empty
    
    Throws:
    
    IllegalStateException - if stream contains more than one element
  - onClose
```
public DoubleStream onClose(Runnable closeHandler)
```
    Adds close handler to the current stream.
    This is an intermediate operation.
    
    Parameters:
    
    closeHandler - an action to execute when the stream is closed
    
    Returns:
    
    the new stream with the close handler
    
    Since:
    
    1.1.8
  - close
```
public void close()
```
    Causes close handler to be invoked if it exists. Since most of the stream providers are lists or arrays, it is not necessary to close the stream.
    
    Specified by:
    
    close in interface Closeable
    
    Specified by:
    
    close in interface AutoCloseable
    
    Since:
    
    1.1.8

Class DoubleStream

Method Summary

Methods inherited from class java.lang.Object

Method Detail

empty

of

of

of

generate

iterate

iterate

concat

iterator

custom

boxed

filter

filterIndexed

filterIndexed

filterNot

map

mapIndexed

mapIndexed

mapToObj

mapToInt

mapToLong

flatMap

distinct

sorted

sorted

sample

peek

scan

scan

takeWhile

takeUntil

dropWhile

limit

skip

forEach

forEachIndexed

forEachIndexed

reduce

reduce

toArray

collect

sum

min

max

count

average

anyMatch

allMatch

noneMatch

findFirst

findLast

single

findSingle

onClose

close