cdenninger

Calculate Field Tool and Python

Discussion created by cdenninger on Jul 12, 2011
Latest reply on Jul 11, 2013 by amontgomery3030
I'd think this one should be easy. 
How do I use my input parameters, to automatically update my Calculate Field expression, within a Python script?  I thought I had it, but I receieve an error.

In my script I would like portions of the expression in the Calculate Field line to change as my input parameters change.  If I force the expression like this, it works:
"( !SUM_POP10! / !SUM_SUM_POP10! )*100", "PYTHON")

But I need both of the fields (either side of the "/" line) in that expression to change based upon one of my input paramters I choose, here:  
popfield = gp.GetParameterAsText(2) #population field

Here is how I have it and where I beleive the Error is coming from; not sure what it doesn't like:
arcpy.CalculateField_management(outputfc, percentfield, '"('+str(popfield)+'/SUM_'+str(popfield)+')*100"', "PYTHON")


Again, as the "popfield =" paramter changes, so does the expression.  So as I choose a new "SUM_POPxx" field, the expression automatically changes with it.

I'd appreciate any assistance.  Thank you.

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