Checking to see if a label exists

Hi,
I was wondering how i check to see if a label exists. Have tried

objectexists(label(item,"sampleLabel")) but it doesn't work, (presumeably because a label isn't an object but a variable?)

I have also tried an if statement querying the label value but it appears neither the if or else blocks are entered if the label doesn't exist.

Thanks
Paul

Paul,

I am not sure what happens in your case but for me it is working.

I used the following code in an OnEntry trigger and the print in the Output Console is as expected.

if(objectexists(label(item,"sampleLabel"))) {pr();pt("Label exists!");} else {pr();pt("Label does not exists!");}

The return you get from objectexists() is 1 (TRUE) or 0 (FALSE).

I am sure you know that labels because they are strings are case sensitive. So it makes a difference if you write SampleLabel or sampleLabel.

Anyway, please try again and tell us what you figure out.

Good success.
tom the (A)tom

P.S.: objectexists() works for nodes so it does not matter if it is a label, a variable or an object.

Some points to keep in mind:

1) If a label doesn't exist it will return 0 as it's value.
2) Labels are nodes inside of the "labels" node inside of the object. The objectexists() command is checking to see if the node exists or not, so it doesn't matter if you pass it an actual object node or any other type of node.
3) Instead of the label name you can use its rank in the label, getlabelnum/str, and setlabelnum/str commands. This reduces the chance or spelling the label name wrong but increases the chance of getting the wrong label if you are unsure of its rank.

Based on your post I would make a quick check of your if statements to make sure that you are using "==" and not "=". The double equal sign is a check for equallity and the single equal sign is used for setting onething equal to another. This is a common mistake.

The formula Tom provided should get you the result you are looking for. If you are checking to see if the label does not exist, simply put a "!" infront of the "objectexists" command in Tom's forumula.

Good Luck,
Brandon

Thanks Tom/ Brandon,

Unfortuneately i didn't keep my original model i was testing this stuff in but i have clearly stuffed something up (wouldn't be the first time i used an assignment operator by mistake i admit)

Tom your code worked perfectly and i also tried it using your first point Brandon to achieve the same thing (returning a value of 0 if it doesn't exist) and both worked perfectly.

Nice to know that object is a generic term for all nodes, my malfunctioning model had me second guessing myself there...

Cheers
Paul