reactive: Sample never completes if the sampler sequence completes before the sampled sequence
Is this expected behavior? It looks to me that if sampler terminates, then there is a guarantee that there will be no more values coming out of Sample, and that it could be safely terminated. I was surprised to find that it never terminates. Is there some problematic scenario where the current behavior would be useful?
To reproduce:
var data = Observable.Timer(TimeSpan.Zero, TimeSpan.FromSeconds(0.5)).Take(10);
var sampler = Observable.Timer(TimeSpan.FromSeconds(1));
var result = data.Sample(sampler).Materialize();
result.Subscribe(Console.WriteLine);
Console.ReadLine();
About this issue
- Original URL
- State: closed
- Created 8 years ago
- Comments: 31 (16 by maintainers)
Commits related to this issue
- This fixes https://github.com/dotnet/reactive/issues/179: When the sampling-observable would terminate earlier than the source observable, the resulting observable would never terminate. — committed to danielcweber/reactive by danielcweber 6 years ago
- This fixes https://github.com/dotnet/reactive/issues/179: When the sampling-observable would terminate earlier than the source observable, the resulting observable would never terminate. — committed to danielcweber/reactive by danielcweber 6 years ago
- This fixes https://github.com/dotnet/reactive/issues/179: When the sampling-observable would terminate earlier than the source observable, the resulting observable would never terminate. — committed to danielcweber/reactive by danielcweber 6 years ago
- Fix https://github.com/dotnet/reactive/issues/179: When the sampling-observable would terminate earlier than the source observable, the resulting observable would never terminate. — committed to danielcweber/reactive by danielcweber 6 years ago
- Fix https://github.com/dotnet/reactive/issues/179: When the sampling-observable would terminate earlier than the source observable, the resulting observable would never terminate. (#520) — committed to dotnet/reactive by danielcweber 6 years ago
- Fix https://github.com/dotnet/reactive/issues/179: When the sampling-observable would terminate earlier than the source observable, the resulting observable would never terminate. (#520) — committed to dotnet/reactive by danielcweber 6 years ago
@RxDave cool, I never noticed
DefaultIfEmpty. However, it looks like you still need to couple it with aTakeLast(1), because if the sequence is non-empty it just starts streaming all the elements from the beginning, which is not what you want if you want to “TakeUntil the end”.However, after checking just now I think I found an even better alternative:
LastOrDefaultAsyncreturns the last element of an observable sequence or a default value if no such element exists. I think I’ll use this one from now on, nice!I think this is due to the
dataobservable never completing, and is by design. Here’s a snapshot of how it looks as an Rx marble diagram:Note where the sequence terminates…