topic Re: Formula differences in Python Questions

Formula differences

JamesCrandall — Thu, 27 Sep 2012 11:41:53 GMT

ArcGIS 9.3.1

I am attempting to calculate a field with a specific formula, which actually works correctly when I plug it into the FieldCalculator in ArcGIS 9.3.1 --- however, I am getting a different result when I place the formula into a Python script.

edit: "fff" is just a field that holds an incremental value starting at 1.

This works in the Field Calculator:
40 - (Int(( [fff] - 1) / 35) + 1) + 1

My attempt to calc the field in the script is like:

rowsr = gp.UpdateCursor(outLabelsFC) rowr = rowsr.Next() i = 1 while row:       rowr.setvalue("row", (40 - ((rowr.fff - 1) / 35) + 1) + 1)       rowsr.updateRow(rowr)       i = i + 1       rowr = rowsr.Next()

Python doesn't like the "Int", so I have tried:
40 - ((rowr.fff - 1) / 35) + 1) + 1
and...
40 - (long((rowr.fff - 1) / 35)) + 1) + 1

Both of the above generate a different result from run in the field calculator. Can you help explain why or what I am missing here?

Thanks!

Re: Formula differences

NeilAyres — Thu, 27 Sep 2012 12:20:19 GMT

Py is case sensitive so "Int" should be "int".
Then in your 2 calculation statements you a have mismatch in the brackets.
Have you tried testing this in the python ide directly.
Cheers,
N

Re: Formula differences

JamesCrandall — Thu, 27 Sep 2012 12:30:26 GMT

Py is case sensitive so "Int" should be "int".
Then in your 2 calculation statements you a have mismatch in the brackets.
Have you tried testing this in the python ide directly.
Cheers,
N

Thank you, Neil.

I simply needed to change Int to int. Jumping from C#.NET/VB.NET to Python (I am new to Python) and creating Geoprocessing objects has been interesting. Simple things can really trip you up and seem to be quite difficult to pickup for some reason!

Thanks again.