Generic Structure

Publishers.Sequence

A publisher that publishes a given sequence of elements.

Declaration

struct Sequence<Elements, Failure> where Elements : Sequence, Failure : Error

Overview

When the publisher exhausts the elements in the sequence, the next request causes the publisher to finish.

Topics

Initializers

init(sequence: Elements)

Creates a publisher for a sequence of elements.

Instance Properties

let sequence: Elements

The sequence of elements to publish.

Instance Methods

func assertNoFailure(String, file: StaticString, line: UInt) -> Publishers.AssertNoFailure<Publishers.Sequence<Elements, Failure>>

Raises a fatal error when its upstream publisher fails, and otherwise republishes all received input.

func assign<Root>(to: ReferenceWritableKeyPath<Root, Elements.Element>, on: Root) -> AnyCancellable

Assigns the value of a KVO-compliant property from a publisher.

func `catch`<P>((Failure) -> P) -> Publishers.Catch<Publishers.Sequence<Elements, Failure>, P>

Handles errors from an upstream publisher by replacing it with another publisher.

func collect(Int) -> Publishers.CollectByCount<Publishers.Sequence<Elements, Failure>>

Collects up to the specified number of elements, and then emits a single array of the collection.

func compactMap<T>((Elements.Element) -> T?) -> Publishers.CompactMap<Publishers.Sequence<Elements, Failure>, T>

Calls a closure with each received element and publishes any returned optional that has a value.

func contains(Elements.Element) -> Publishers.Contains<Publishers.Sequence<Elements, Failure>>

Publishes a Boolean value upon receiving an element equal to the argument.

func contains(Elements.Element) -> Result<Bool, Failure>.Publisher
func count() -> Publishers.Count<Publishers.Sequence<Elements, Failure>>

Publishes the number of elements received from the upstream publisher.

func count() -> Result<Int, Failure>.Publisher
func decode<Item, Coder>(type: Item.Type, decoder: Coder) -> Publishers.Decode<Publishers.Sequence<Elements, Failure>, Item, Coder>

Decodes the output from upstream using a specified TopLevelDecoder. For example, use JSONDecoder.

func drop<P>(untilOutputFrom: P) -> Publishers.DropUntilOutput<Publishers.Sequence<Elements, Failure>, P>

Ignores elements from the upstream publisher until it receives an element from a second publisher.

func encode<Coder>(encoder: Coder) -> Publishers.Encode<Publishers.Sequence<Elements, Failure>, Coder>

Encodes the output from upstream using a specified TopLevelEncoder. For example, use JSONEncoder.

func first() -> Publishers.First<Publishers.Sequence<Elements, Failure>>

Publishes the first element of a stream, then finishes.

func last() -> Publishers.Last<Publishers.Sequence<Elements, Failure>>

Only publishes the last element of a stream, after the stream finishes.

func last(where: (Elements.Element) -> Bool) -> Publishers.LastWhere<Publishers.Sequence<Elements, Failure>>

Only publishes the last element of a stream that satisfies a predicate closure, after the stream finishes.

func makeConnectable() -> Publishers.MakeConnectable<Publishers.Sequence<Elements, Failure>>

Creates a connectable wrapper around the publisher.

func map<T>((Elements.Element) -> T) -> Publishers.Map<Publishers.Sequence<Elements, Failure>, T>

Transforms all elements from the upstream publisher with a provided closure.

func mapError<E>((Failure) -> E) -> Publishers.MapError<Publishers.Sequence<Elements, Failure>, E>

Converts any failure from the upstream publisher into a new error.

func max() -> Publishers.Comparison<Publishers.Sequence<Elements, Failure>>

Publishes the maximum value received from the upstream publisher, after it finishes.

func max() -> Optional<Publishers.Sequence<Elements, Failure>.Output>.Publisher
func merge(with: Publishers.Sequence<Elements, Failure>) -> Publishers.MergeMany<Publishers.Sequence<Elements, Failure>>

Combines elements from this publisher with those from another publisher of the same type, delivering an interleaved sequence of elements.

func merge<B, C>(with: B, C) -> Publishers.Merge3<Publishers.Sequence<Elements, Failure>, B, C>

Combines elements from this publisher with those from two other publishers, delivering an interleaved sequence of elements.

func merge<B, C, D>(with: B, C, D) -> Publishers.Merge4<Publishers.Sequence<Elements, Failure>, B, C, D>

Combines elements from this publisher with those from three other publishers, delivering an interleaved sequence of elements.

func merge<B, C, D, E>(with: B, C, D, E) -> Publishers.Merge5<Publishers.Sequence<Elements, Failure>, B, C, D, E>

Combines elements from this publisher with those from four other publishers, delivering an interleaved sequence of elements.

func merge<B, C, D, E, F>(with: B, C, D, E, F) -> Publishers.Merge6<Publishers.Sequence<Elements, Failure>, B, C, D, E, F>

Combines elements from this publisher with those from five other publishers, delivering an interleaved sequence of elements.

func merge<B, C, D, E, F, G>(with: B, C, D, E, F, G) -> Publishers.Merge7<Publishers.Sequence<Elements, Failure>, B, C, D, E, F, G>

Combines elements from this publisher with those from six other publishers, delivering an interleaved sequence of elements.

func merge<B, C, D, E, F, G, H>(with: B, C, D, E, F, G, H) -> Publishers.Merge8<Publishers.Sequence<Elements, Failure>, B, C, D, E, F, G, H>

Combines elements from this publisher with those from seven other publishers, delivering an interleaved sequence of elements.

func min() -> Publishers.Comparison<Publishers.Sequence<Elements, Failure>>

Publishes the minimum value received from the upstream publisher, after it finishes.

func min() -> Optional<Publishers.Sequence<Elements, Failure>.Output>.Publisher
func output(at: Int) -> Publishers.Output<Publishers.Sequence<Elements, Failure>>

Publishes a specific element, indicated by its index in the sequence of published elements.

func output<R>(in: R) -> Publishers.Output<Publishers.Sequence<Elements, Failure>>

Publishes elements specified by their range in the sequence of published elements.

func reduce<T>(T, (T, Elements.Element) -> T) -> Publishers.Reduce<Publishers.Sequence<Elements, Failure>, T>

Applies a closure that accumulates each element of a stream and publishes a final result upon completion.

func removeDuplicates() -> Publishers.RemoveDuplicates<Publishers.Sequence<Elements, Failure>>

Publishes only elements that don’t match the previous element.

func replaceNil<T>(with: T) -> Publishers.Map<Publishers.Sequence<Elements, Failure>, T>

Replaces nil elements in the stream with the proviced element.

func retry(Int) -> Publishers.Retry<Publishers.Sequence<Elements, Failure>>

Attempts to recreate a failed subscription with the upstream publisher using a specified number of attempts to establish the connection.

func scan<T>(T, (T, Elements.Element) -> T) -> Publishers.Scan<Publishers.Sequence<Elements, Failure>, T>

Transforms elements from the upstream publisher by providing the current element to a closure along with the last value returned by the closure.

func setFailureType<E>(to: E.Type) -> Publishers.SetFailureType<Publishers.Sequence<Elements, Failure>, E>

Changes the failure type declared by the upstream publisher.

func subscribe<S>(S) -> AnyCancellable

Attaches the specified Subscriber to this Publisher.

func subscribe<S>(S)

Attaches the specified subscriber to this publisher.

func subscribe<S>(on: S, options: S.SchedulerOptions?) -> Publishers.SubscribeOn<Publishers.Sequence<Elements, Failure>, S>

Specifies the scheduler on which to perform subscribe, cancel, and request operations.

func switchToLatest() -> Publishers.SwitchToLatest<Elements.Element, Publishers.Sequence<Elements, Failure>>

Flattens the stream of events from multiple upstream publishers to appear as if they were coming from a single stream of events.

func throttle<S>(for: S.SchedulerTimeType.Stride, scheduler: S, latest: Bool) -> Publishers.Throttle<Publishers.Sequence<Elements, Failure>, S>

Publishes either the most-recent or first element published by the upstream publisher in the specified time interval.

func tryCompactMap<T>((Elements.Element) -> T?) -> Publishers.TryCompactMap<Publishers.Sequence<Elements, Failure>, T>

Calls an error-throwing closure with each received element and publishes any returned optional that has a value.

func tryDrop(while: (Elements.Element) -> Bool) -> Publishers.TryDropWhile<Publishers.Sequence<Elements, Failure>>

Omits elements from the upstream publisher until an error-throwing closure returns false, before republishing all remaining elements.

func tryLast(where: (Elements.Element) -> Bool) -> Publishers.TryLastWhere<Publishers.Sequence<Elements, Failure>>

Only publishes the last element of a stream that satisfies a error-throwing predicate closure, after the stream finishes.

func tryMap<T>((Elements.Element) -> T) -> Publishers.TryMap<Publishers.Sequence<Elements, Failure>, T>

Transforms all elements from the upstream publisher with a provided error-throwing closure.

func tryPrefix(while: (Elements.Element) -> Bool) -> Publishers.TryPrefixWhile<Publishers.Sequence<Elements, Failure>>

Republishes elements while a error-throwing predicate closure indicates publishing should continue.

func tryReduce<T>(T, (T, Elements.Element) -> T) -> Publishers.TryReduce<Publishers.Sequence<Elements, Failure>, T>

Applies an error-throwing closure that accumulates each element of a stream and publishes a final result upon completion.

func tryScan<T>(T, (T, Elements.Element) -> T) -> Publishers.TryScan<Publishers.Sequence<Elements, Failure>, T>

Transforms elements from the upstream publisher by providing the current element to an error-throwing closure along with the last value returned by the closure.

func zip<P>(P) -> Publishers.Zip<Publishers.Sequence<Elements, Failure>, P>

Combine elements from another publisher and deliver pairs of elements as tuples.

func zip<P, Q>(P, Q) -> Publishers.Zip3<Publishers.Sequence<Elements, Failure>, P, Q>

Combine elements from two other publishers and deliver groups of elements as tuples.

func zip<P, Q, R>(P, Q, R) -> Publishers.Zip4<Publishers.Sequence<Elements, Failure>, P, Q, R>

Combine elements from three other publishers and deliver groups of elements as tuples.

Relationships

Conforms To

See Also

Convenience Publishers

struct Publishers.Catch

A publisher that handles errors from an upstream publisher by replacing the failed publisher with another publisher.

Beta

Beta Software

This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.

Learn more about using Apple's beta software