topic TRACE - directly enter an expression in QlikView

TRACE - directly enter an expression

datanibbler — Tue, 24 Feb 2015 08:21:58 GMT

Hi,

is there any way I can make the TRACE command put in the log the result of an expression without first putting this into a variable?

I have tried with like

>> $(=Weekday(Today(0))) <<

the way you do in set_expressions, but that didn't work.

I also tried with quotes around the whole, but that didn't work either - then it read like

>> TRACE ' '; <<

in the log, which isn't quite what I want ...

That didn't work, however. I then created a variable first and then put this into the TRACE command, like

>> LET v_message = Weekday(Today(0)); <<

>> TRACE $(v_message); <<

>> LET v_message = NULL(); <<

That works. That is okay, but it should be possible to use this expression directly, no?

Thanks a lot!

Best regards,

DataNibbler

Re: TRACE - directly enter an expression

marcus_sommer — Wed, 25 Feb 2015 08:51:44 GMT

Hi DataNibbler,

I think it would only directly work if there are a possibilty to create an adhoc-variable within the script, like:

trace $(=function());

Therefore a workaround would be needed, maybe with a subroutine like this which could be outsourced in an include-variable for a global using:

sub ShowTraceStament(typ, statement)

if '$(typ)' = 'string' then

let vTrace = '$(statement)';

else

let vTrace = $(statement);

end if

trace $(vTrace);

end sub

call ShowTraceStament('string', 'hallo welt')

call ShowTraceStament('numeric', 'weekday(today())')

- Marcus

Re: TRACE - directly enter an expression

datanibbler — Wed, 25 Feb 2015 09:06:40 GMT

Ah.

And those ad-hoc-variables don't work in the script, do they? For that's what I tried ...

Thanks for helping! A subroutine seems to be a little much ado for that, though - and it wouldn't really make things easier for that's pretty much what I have now.

I will try putting some more code in that INCLUDE, that should do the job well enough.

Thanks a lot!

Best regards,

DataNibbler

Re: TRACE - directly enter an expression

mmarchese — Thu, 30 Apr 2020 18:45:41 GMT

Inspired by marcus's helpful answer, I made a simpler version. (I didn't see any reason for the custom subroutine to handle tracing plain text when the built-in Trace() already does that just fine.)

Sub EvaluateAndTrace(expression) Let e = $(expression); Trace $(e); Let e = ; End Sub

Usage:

Call EvaluateAndTrace('Weekday(Today())'); // Thu

Lots of examples to help with understanding the nuances:

Trace hello; // hello Trace Weekday(Today()); // Weekday(Today()) Call EvaluateAndTrace('Weekday(Today())'); // Thu Set var = Weekday(Today()); Trace var // var Trace $(var); // Weekday(Today()) Call EvaluateAndTrace(var); // Thu Set innerVar = Today(); Set var = Weekday($(innerVar)); Trace var; // var Trace $(var); // Weekday(Today()) Call EvaluateAndTrace(var); // Thu

Re: TRACE - directly enter an expression

shane_spencer — Thu, 21 Mar 2024 07:24:23 GMT

Awesome! I'm crunching some very big data and this will allow me to easily tune the script!