topic Calculate Field in Python Questions

Calculate Field

HollyZhang1 — Fri, 07 Feb 2014 22:29:21 GMT

I am using ArcPy 10.2 CalculateField management to format a field from an existing field.
e.g. from 123456789 to {12-3456-789}
It works good using attribute table, but it shows "syntax error" when using python scripting.
Anyone has any solution?
Thanks.

Re: Calculate Field

RichardFairhurst — Fri, 07 Feb 2014 22:38:41 GMT

I am using ArcPy 10.2 CalculateField management to format a field from an existing field.
e.g. from 123456789 to {12-3456-789}
It works good using attribute table, but it shows "syntax error" when using python scripting.
Anyone has any solution?
Thanks.

What does the calculation look like in the Python script?

Re: Calculate Field

HollyZhang1 — Fri, 07 Feb 2014 23:08:28 GMT

What does the calculation look like in the Python script?

in the Python script like:
"{"+!field![:2]+"-"+!field![2:6]+"-"+!field![6:]+"}"
it works good in attribute table!
By the way, !field! is string.

Re: Calculate Field

RichardFairhurst — Sat, 08 Feb 2014 01:35:14 GMT

in the Python script like:
"{"+!field![:2]+"-"+!field![2:6]+"-"+!field![6:]+"}"
it works good in attribute table!
By the way, !field! is string.

This has to be quoted and fed in as an expression to the CalculateField_management tool. I seriously hope you did not actually create a field in a table called field. That is a keyword that will cause problems. If it has another name in the table use that name. Anyway, something like:

import arcpy
from arcpy import env

# Set environment settings
env.workspace = "C:/data/airport.gdb"

# Set local variables
inFeatures = "parcels"
fieldName = "IDValue"
expression = '"{"+!IDValue![:2]+"-"+!IDValue![2:6]+"-"+!IDValue![6:]+"}"'

# Execute CalculateField
arcpy.CalculateField_management(inFeatures, fieldName, expression, "PYTHON_9.3")