topic Re: Dropping variables in QlikView

Dropping variables

priyarane — Wed, 09 Sep 2015 18:58:10 GMT

Hi Community,

How to drop variables.

I have 50 variables and I have loaded from excel by for loop and I wanted to drop all together.

Note: I have all the variable names in excel.

Re: Dropping variables

marcus_sommer — Wed, 09 Sep 2015 19:01:58 GMT

Then loop through the variables again and assign null() to them:

for ...

let variable = null();

- Marcus

Re: Dropping variables

priyarane — Wed, 09 Sep 2015 19:06:55 GMT

This is the for loop I am using so how to use your look, Could you please let me know briefly?

let vi=noofrows('Tablenam');

for i=0 to (vi-1)

let vVar=peek('vVarname',i,'Expression')

let $(vVar)=peek('Expression',i,'Expression')

next i;

Re: Dropping variables

chriscammers — Wed, 09 Sep 2015 19:31:31 GMT

you could drop the variables once they are in the front end if you modify this macro I found on Qlik Maven

If these are not supposed to be in the document then I would set them to Null() before the end of the script.

Thanks

Chris

Re: Dropping variables

sasiparupudi1 — Wed, 09 Sep 2015 19:46:41 GMT

Try

let vi=noofrows('Tablenam');

for i=0 to (vi-1)

//let vVar=peek('vVarname',i,'Expression');

//let $(vVar)=peek('Expression',i,'Expression');

let vVar=Null();

next i;

Re: Dropping variables

priyarane — Thu, 10 Sep 2015 05:25:32 GMT

Hi sasidhar,

Value is changing but name also should drop, how can I do it.

Thank you

Re: Dropping variables

marcus_sommer — Thu, 10 Sep 2015 05:31:20 GMT

See: QlikTip #9: Deleting variables via user-interface, within the load-script or by using macros (translated)

- Marcus

Re: Dropping variables

tresB — Thu, 10 Sep 2015 05:31:57 GMT

Variables (names) can't be deleted that way. You can manually delete them from Settings->Variable Overview. However, script variables would get populated again after a reload.

Re: Dropping variables

jonathandienst — Thu, 10 Sep 2015 06:06:05 GMT

If a variable does not exist when the reload starts, and is set to a value in the script and set to null before he script closes, it will be automagically dropped.

Use

Set vVar =;

Let vVar = null();

Re: Dropping variables

jonathandienst — Thu, 10 Sep 2015 06:10:16 GMT

During development and debugging, these variables are sometimes not dropped when the the script is aborted before completion. For this reason, I define script-only variables with a z prefix (rather than the v prefix which I normally use).

Once development is complete, I can sort the variables in the variabe overview and delete all the z* variables. I can also see if a set var = null is missing because the z* variable survives the reload.

Just a tip...

Re: Dropping variables

tresB — Thu, 10 Sep 2015 06:14:58 GMT

Thanks Jonathan, for the correction. You are right, I tested. So I have to correct:

You can manually delete them from Settings->Variable Overview. However, script variables would get populated again after a reload.

It would actually get deleted if the variables are assigned(before the script ends) with null or nothing (soft null) like you said, like:

Let vVarName=;

Let vVarNam=null();

Re: Dropping variables

oknotsen — Thu, 10 Sep 2015 09:10:32 GMT

If you have no problem doing it in the front-end, you might as well just go to the variable overview and click on delete a few times.

Re: Dropping variables

Peter_Cammaert — Thu, 10 Sep 2015 09:47:01 GMT

This should work (based on your code):

let vi=noofrows('Tablenam');

for i=0 to (vi-1)

let vVar=peek('vVarname',i,'Expression');

let $(vVar)=;

let vi=; // Don't forget these

let vVar=;

Peter