Operator - Empty, Never and Throw

classmethodObservable.empty(scheduler=None)

create an Observable that emits no items but terminates normally

Returns an empty observable sequence, using the specified scheduler to send out the single OnCompleted message.

1 - res = rx.Observable.empty() 2 - res = rx.Observable.empty(rx.Scheduler.timeout)

scheduler – Scheduler to send the termination call on.

Returns an observable sequence with no elements.

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Observable.empty();

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classmethodObservable.never()

create an Observable that emits no items and does not terminate

Returns a non-terminating observable sequence, which can be used to denote an infinite duration (e.g. when using reactive joins).

Returns an observable sequence whose observers will never get called.

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Observable.never();

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classmethodObservable.throw(exception, scheduler=None)

Returns an observable sequence that terminates with an exception, using the specified scheduler to send out the single OnError message.

1 - res = rx.Observable.throw_exception(Exception(‘Error’)) 2 - res = rx.Observable.throw_exception(Exception(‘Error’),

rx.Scheduler.timeout)

Keyword arguments: exception – An object used for the sequence’s termination. scheduler – Scheduler to send the exceptional termination call on. If

not specified, defaults to ImmediateScheduler.

Returns the observable sequence that terminates exceptionally with the specified exception object.

classmethodObservable.throw_exception(exception, scheduler=None)

Returns an observable sequence that terminates with an exception, using the specified scheduler to send out the single OnError message.

1 - res = rx.Observable.throw_exception(Exception(‘Error’)) 2 - res = rx.Observable.throw_exception(Exception(‘Error’),

rx.Scheduler.timeout)

Keyword arguments: exception – An object used for the sequence’s termination. scheduler – Scheduler to send the exceptional termination call on. If

not specified, defaults to ImmediateScheduler.

Returns the observable sequence that terminates exceptionally with the specified exception object.

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