Script Tester and name 'isNull' is not defined

Ignition
1

Hi!

I have a problem to use isNull() function within Script Tester.
I am getting error:

Traceback (most recent call last):
File “”, line 8, in
NameError: name ‘isNull’ is not defined

What I am thinking is that I have to import some module but I do not have idea which module.
Is there any manual regarding scripting and modules which has to be import to be able to use certain function?

Thank you

2

Hi, falko,

Null in python is None. There are two ways to check for something being None:

If value is None: doSomething else: doSomethingElse

If value == None: doSomething else: doSomethingElse

Or, to check if it’s not None:

If value is not None: doSomething else: doSomethingElse

If value != None: doSomething else: doSomethingElse

3 Likes
3

Thanks Jordan,

That is working.
But still iI have problem with some Expression Functions (Appendix B. Expression Functions from Ignition help). I try to use some of them in Interactive Script Tester, but I am getting similar error, for example:
NameError: name ‘toradians’ is not defined
or
NameError: name ‘toInteger’ is not defined

Question is where I can use them if they are not working in Script Tester?

4

Ah. Expression language and Scripting are two separate animals.

Expressions are used in Tags and Transaction groups. Scripts are python code.

5

Thanks Jordan,

That was something what I had to know.
Thanks a lot.