From Friday, April 19th (11:00 PM CDT) through Saturday, April 20th (2:00 PM CDT), 2024, ni.com will undergo system upgrades that may result in temporary service interruption.

We appreciate your patience as we improve our online experience.

NI TestStand

cancel
Showing results for 
Search instead for 
Did you mean: 

Can you use case statements in Post-Expressions

I'm trying to figure out how to use the Post-Expression like an if else but I'm having difficulty finding a way to implement for cases that have more than just two options.

 

Anyone ever done this?

0 Kudos
Message 1 of 5
(4,822 Views)

Expressions are just.... expressions. There are no loops, variable declarations, case statements, if/then's, or method definitions.

 

However, you can use the ? :  conditional operators as a substitute for if/then and case, such as:

 

Locals.number =
    Locals.string == "A" ? 1 :
    Locals.string == "B" ? 2 :
    Locals.string == "C" ? 3 :
    4

 

 

The syntax is:

 

<boolean> ? <value-if-true> : <value-if-false>

Message 2 of 5
(4,817 Views)

Yeah, I have a LabVIEW vi that runs the same 9 tests at 3 different voltages, what I was looking to do was use Locals.Index (iterative variable) to determine the ReportText to be written to my datasheet, problem is the ? : only would cover two options, and I need 3 and sometime even more in other tests that perform repetative loops at different voltage levels.

 

I've come across several posts asking this same question, but they were a few years old, was hoping there was a "new" way that I just had not come across yet.

 

Thanks.

0 Kudos
Message 3 of 5
(4,814 Views)

Can you use multiple ? operators to get more than two options? The example I included did that.

0 Kudos
Message 4 of 5
(4,812 Views)

I'll have to give it a try, but I had already re-coded my program before I got your response, but I thought I had tried a version of this method and TestStand kept throwing evaluation errors because of the ?, which is what sent me to the discussion forums.

 

 

0 Kudos
Message 5 of 5
(4,810 Views)