Concat Bug

Question

Concat doesn't seem to be working for me. I'm running the 3.5 SP1 build (1.0.2067.0).

Am I doing something silly?

var five = Observable.Interval(TimeSpan.FromSeconds(5));
var one = Observable.Interval(TimeSpan.FromSeconds(1));
five.Concat(one).Subscribe(l => Console.WriteLine(DateTime.Now + " : " +l));

Output:

17/12/2009 10:21:00 AM : 0
17/12/2009 10:21:05 AM : 1
17/12/2009 10:21:10 AM : 2

We are missing the 1 second "ticks".

Thanks,
James

Answer 1

Concat waits for the left source to complete before subscribing to the right source.  Since Observable.Interval never completes then five.Concat(one) == five.

Perhaps, what you are looking for is Merge which interleaves the messages from the two sources.

Answer 2

Ahh - Thanks Wes!

Answer 3

Also, check out http://rxwiki.wikidot.com/101samples and see if the concat samples help/make sense.