Last(#2) or sum(#2) ?

[Kai-Kai]

Hello.

I want to make a trigger which test twice the disponibility of a webpage before displaying alert.
When the web is ok, the item "failed step" is on 0.

So my question is, is the right trigger :
***.last(#2)#0
or
***.sum(#2)>1
?

I don't really see if last(#2)#0 test if ONE OF the 2 last values is different from 0, or if THE TWO last values are both different from 0 ?
If it's the first, I have to use sum to do what I want...

When I test, it seems to wait to receive 2 bad values to go in alert, but, when it receives a good one, it seems to stay in alert during a few time... I'm not sur I've right understood the way last() works...

Thanks in advance.

[Kai-Kai]

After reading the documentation again and making more tests... I think I've misunderstood the way last works...

In fact last(#2) mean the value before the last one, last(#3) the value before last(#2) etc...

So, I think the way to do what I want is sum(#2)>1 isn't it ?

[Calimero]

There's also .count() that allows you to... count how many times you got value X over the last #N checks or the last T seconds.

.sum() is fine as long as you only have 0 or 1 as a return value. But some of the simple checks return 0 for failure, 1 for success and 2 for timeout. So .sum() is not appropriate on such items.

[Kai-Kai]

Yeah, you're right... I haven't thought about count() before.
It's effectively a good way to do that.

In my case, I can use count or sum, but in cases where the value is another number than 0 or 1, count is effectively a better solution.

The use of count with a third parameter is good here. Something like :
***.count(#2,0,"gt")>1
will count the number of values greater than 0 in the 2 last values. I think it will give the same result than sum in this case.

Thanks again for your answer.
(You really have the answer to all of my questions ^^)