Hopefully an easy question about Nil checking

I’m having trouble handling an XML field that may or may not contanin nil values. How can I check to see if a field contains an nil value and write one if it doesnt? I’m usung the account number in naming a file that iguana creates so I put in an underscore where it doesn’t have one. This if statement works if I have a value, but if I don’t have an account number, then I get an error “Index 1 is out of bounds”

if patientXML.PatientAccountNumber[1] then
      patientAccount = patientXML.PatientAccountNumber[1]:S()..'_'
      else
      patientAccount = '_'
   end
end

Thanks in adavance for any insight you can offer.

M.R. McBee

If you change it to this, you’ll probably have more luck:

if #patientXML.PatientAccountNumber > 0 and patientXML.PatientAccountNumber[1] then
      patientAccount = patientXML.PatientAccountNumber[1]:S()..'_'
      else
      patientAccount = '_'
   end
end

That will ensure that patientXML.PatientAccountNumber has a child before drilling into it.

I have a feeling that this is exactly what you need:

http://wiki.interfaceware.com/638.html

Then you can write the code much more elegantly in one line:

patientAccount = patientXML.PatientAccountNumber:text()..’_’

Where the text() function is a general reusable ‘node extension’ function.

The source to the text() function is in the above wiki page. You put that into a general re-usable module that you use anytime you are dealing with XML.

It make the code more readable and easier to understand what it’s doing. Hope that helps!

Thanks guys, I did a few searches through the wiki and didn’t find that one. But that’s a perfect solution, I appreaciate your help. (Kevins)

M.R. McBee