topic Re: How to pass a function to a custom variable in QlikView

How to pass a function to a custom variable

JSamuel_MHV — Wed, 25 Nov 2020 16:16:04 GMT

I've created a custom variable that accepts a date parameter and returns a value. It works as expected when a date is passed through to the function, but doesn't work when a function is passed through.

For example, my custom variable VDate_Calc is defined as: monthname($1). Passing today's date to the variable like so: =$(vDate_Calc(Today())) returns Apr 2020 as expected. However, I receive an error when I try passing a function through to the variable like so: =$(vDate_Calc(AddMonths(Today(),1)))

The error message reads "Error: Error in expression: AddMonths takes 2-3 parameters". However AddMonths(Today(),1) returns the correct value 24/05/2020.

Any suggestions on how to fix this error?

Thanks!

Re: How to pass a function to a custom variable

marcus_sommer — Fri, 24 Apr 2020 04:33:53 GMT

The comma from the function will be interpreted as a parameter-delimiter to the variable and therefore it failed. This means you need to ensure that the function is calculated within the variable or you need a different approach. To the first you could try something like this:

$(vDate_Calc($(=AddMonths(Today(),1))))

- Marcus

Re: How to pass a function to a custom variable

JSamuel_MHV — Fri, 24 Apr 2020 04:42:36 GMT

This approach doesn't raise an error, but it returns an incorrect value = Dec 1899. Looks like the AddMonths function doesn't work properly when nested within a custom variable?

Re: How to pass a function to a custom variable

marcus_sommer — Fri, 24 Apr 2020 05:59:53 GMT

My suggestion should work within the UI - within the script the feature of creating an adhoc variable with $(= …) isn't available. In general is the approach to nest variables especially if they should contain functions difficult and the efforts to get the various syntax-requirements working much bigger as keeping the logics more simple.

- Marcus