topic Re: Python in Field Calculator in Python Questions

Python in Field Calculator

MatthiasJessen — Sun, 02 Feb 2014 08:39:06 GMT

Hello,

i try to use the index position of a field for an if-clause in the field calculator.

gesamt =

function(arcpy.fieldInfo.findFieldByName(!gesamt!))

Codeblock:

def function(index):
 if (index > 30):
  ergebnis =  (!Join_Count! + !Join_Count_1!)
  return ergebnis
 else:
  return 99

Result:
[ATTACH=CONFIG]31051[/ATTACH]

This way or syntax is probably totaly wrong and i am grateful for any advise or solution.

Thank you

Re: Python in Field Calculator

Luke_Pinner — Sun, 02 Feb 2014 18:44:44 GMT

The fieldInfo object is a property of a Describe object. Its class definition is in the arcpy package, but you don't use it from there (how does arcpy know what layer you are referring to?). See the 1st example in the help.

Try:

arcpy.Describe(layer).fieldInfo.findFieldByName(!gesamt!))

Re: Python in Field Calculator

RichardFairhurst — Sun, 02 Feb 2014 18:50:27 GMT

The fieldInfo object is a property of a Describe object. It's class definition is in the arcpy package, but you don't use it from there (how does arcpy know what layer you are referring to?). See the 1st example in the help.

Try:
arcpy.Describe(layer).fieldInfo.findFieldByName(!gesamt!))

You also have to pass in the !Join_Count! and Join_Count_1! fields through the expression to the codeblock from the same layer. A cursor pair might be easier if this is for a join table calculation with a runtime assigned layer set.

Try

function(arcpy.Describe(layer).fieldInfo.findFieldByName(!gesamt!), arcpy.Describe(layer).fieldInfo.findFieldByName(!Join_Count!), arcpy.Describe(layer).fieldInfo.findFieldByName(!Join_Count_1!)))

def function(index, Join_Count, Join_Count_1)

Re: Python in Field Calculator

MatthiasJessen — Mon, 03 Feb 2014 06:32:09 GMT

Thank you. We solved it with an extern python script and the FieldInfo