Efficient use of case structure

[John_Deans]

I frequently need to trap a variable equal to zero or another number (-1). I have frequently connected the variable to the select input of a case structure set one state to the number I wish to trap using the default case for the normal code. I this more efficient less efficient or no difference to using an "equals zero vi then a Boolean to control a simple true/ false case structure?

[RavensFan]

I don't know.  You could write some test code that does each one repeatedly in a loop and see which takes longer.

But why are you concerned?

[Norbert_B]

To add the following:

What are possible future changes to the code? To be more specific: Does comparing the numeric value to a boolean state (equal, not equal, ...) restrict future changes?

Norbert

[mcduff]

It depends on what is in the case structure. If it is a simple selection then the following snippet is faster, if you have subVIs in your case structure, then you will need a case structure. Note that the Slect function is faster than the case structure, but both a pretty fast. Only if you have a tight loop with millions of points will you start to see the difference.

Cheers,

mcduff

[billko]

In cases where all I care about is if something's true or not - for instance, a string match offset being -1 or not - I test for "T/F" instead of "-1 or other number" so I can use "select" instead of a case structure (provided it's something simple like choosing one value or another).

[edit]

oops, like mcduff

[John_Deans]

In this case the select toll is not appropriate as a decision is made whether or not to run some test software based on the value returned for a data and result index a value of -1, this case, means no data or index so don't run the test