Alphabetical List of Observable Operators

• aggregate( ) — apply a function to each emitted item, sequentially, and emit only the final accumulated value
• all( ) — determine whether all items emitted by an Observable meet some criteria
• amb( ) — given two or more source Observables, emits all of the items from the first of these Observables to emit an item
• buffer( ) — periodically gather items from an Observable into bundles and emit these bundles rather than emitting the items one at a time
• cache( ) — remember the sequence of items emitted by the Observable and emit the same sequence to future Observers
• cast( ) — cast all items from the source Observable into a particular type before reemitting them
• combineLatest( ) — when an item is emitted by either of two Observables, combine the latest item emitted by each Observable via a specified function and emit items based on the results of this function
• concat( ) — concatenate two or more Observables sequentially
• contains( ) — determine whether an Observable emits a particular item or not
• create( ) — create an Observable from scratch by means of a function
• debounce( ) — only emit an item from the source Observable after a particular timespan has passed without the Observable emitting any other items
• defaultIfEmpty( ) — emit items from the source Observable, or emit a default item if the source Observable completes after emitting no items
• defer( ) — do not create the Observable until an Observer subscribes; create a fresh Observable on each subscription
• delay( ) — shift the emissions from an Observable forward in time by a specified amount
• dematerialize( ) — convert a materialized Observable back into its non-materialized form
• distinct( ) — suppress duplicate items emitted by the source Observable
• distinctUntilChanged( ) — suppress duplicate consecutive items emitted by the source Observable
• elementAt( ) — emit item n emitted by the source Observable
• elementAtOrDefault( ) — emit item n emitted by the source Observable, or a default item if the source Observable emits fewer than n items
• empty( ) — create an Observable that emits nothing and then completes
• error( ) — create an Observable that emits nothing and then signals an error
• exists( ) — determine whether an Observable emits any items or not
• filter( ) — filter items emitted by an Observable
• finallyDo( ) — register an action to take when an Observable completes
• first( ) — emit only the first item emitted by an Observable, or the first item that meets some condition
• firstOrDefault( ) — emit only the first item emitted by an Observable, or the first item that meets some condition, or a default value if the source Observable is empty
• flatMap( ) — transform the items emitted by an Observable into Observables, then flatten this into a single Observable
• from( ) — convert an Iterable or a Future into an Observable
• groupBy( ) — divide an Observable into a set of Observables that emit groups of items from the original Observable, organized by key
• ignoreElements( ) — discard the items emitted by the source Observable and only pass through the error or completed notification
• interval( ) — create an Observable that emits a sequence of integers spaced by a given time interval
• isEmpty( ) — determine whether an Observable emits any items or not
• just( ) — convert an object into an Observable that emits that object
• map( ) — transform the items emitted by an Observable by applying a function to each of them
• mapMany( ) — transform the items emitted by an Observable into Observables, then flatten this into a single Observable
• mapManyDelayError( ) — transform the items emitted by an Observable into Observables, then flatten this into a single Observable, waiting to report errors until all error-free observables have a chance to complete
• mapWithIndex( ) — transform the items emitted by an Observable by applying a function to each of them that takes into account the index value of the item
• materialize( ) — convert an Observable into a list of Notifications
• merge( ) — combine multiple Observables into one
• mergeDelayError( ) — combine multiple Observables into one, allowing error-free Observables to continue before propagating errors
• never( ) — create an Observable that emits nothing at all
• observeOn( ) — specify on which Scheduler an Observer should observe the Observable
• ofClass( ) — emit only those items from the source Observable that are of a particular class
• onErrorResumeNext( ) — instructs an Observable to continue emitting items after it encounters an error
• onErrorReturn( ) — instructs an Observable to emit a particular item when it encounters an error
• onExceptionResumeNextViaObservable( ) — instructs an Observable to continue emitting items after it encounters an exception (but not another variety of throwable)
• parallel( ) — split the work done on the emissions from an Observable into multiple Observables each operating on its own parallel thread
• range( ) — create an Observable that emits a range of sequential integers
• reduce( ) — apply a function to each emitted item, sequentially, and emit only the final accumulated value
• retry( ) — if a source Observable emits an error, resubscribe to it in the hopes that it will complete without error
• sample( ) — emit the most recent items emitted by an Observable within periodic time intervals
• scan( ) — apply a function to each item emitted by an Observable, sequentially, and emit each successive value
• sequenceEqual( ) — test the equality of pairs of items emitted by two Observables
• skip( ) — ignore the first n items emitted by an Observable
• skipLast( ) — ignore the last n items emitted by an Observable
• skipWhile( ) and skipWhileWithIndex( ) — discard items emitted by an Observable until a specified condition is false, then emit the remainder
• startWith( ) — emit a specified sequence of items before beginning to emit the items from the Observable
• subscribeOn( ) — specify which Scheduler an Observable should use when its subscription is invoked
• switchOnNext( ) — convert an Observable that emits Observables into a single Observable that emits the items emitted by the most-recently emitted of those Observables
• synchronize( ) — force an Observable to make synchronous calls and to be well-behaved
• take( ) — emit only the first n items emitted by an Observable
• takeLast( ) — only emit the last n items emitted by an Observable
• takeUntil( ) — emits the items from the source Observable until a second Observable emits an item
• takeWhile( ) and takeWhileWithIndex( ) — emit items emitted by an Observable as long as a specified condition is true, then skip the remainder
• throttleFirst( ) — emit the first items emitted by an Observable within periodic time intervals
• throttleLast( ) — emit the most recent items emitted by an Observable within periodic time intervals
• throttleWithTimeout( ) — only emit an item from the source Observable after a particular timespan has passed without the Observable emitting any other items
• timeInterval( ) — emit the time lapsed between consecutive emissions of a source Observable
• timeout( ) — emit items from a source Observable, but issue an exception if no item is emitted in a specified timespan
• timestamp( ) — attach a timestamp to every item emitted by an Observable
• toList( ) — collect all items from an Observable and emit them as a single List
• toSortedList( ) — collect all items from an Observable and emit them as a single, sorted List
• where( ) — filter items emitted by an Observable
• window( ) — periodically subdivide items from an Observable into Observable windows and emit these windows rather than emitting the items one at a time
• zip( ) — combine sets of items emitted by two or more Observables together via a specified function and emit items based on the results of this function