topic Re: add and calculate field in Python Questions

add and calculate field

YinghaiKe — Thu, 29 Sep 2011 22:40:59 GMT

I want to add a field "filename" with "TEXT" format for a shape file and assign this field with the file name. The shape file only has one record. Here is my code:

import arcpy
from arcpy import env

# Set environment settings
env.workspace = "D:/Workspace"

fc = "01055p.shp"
tmp = fcname.split('.')
tmp2 = tmp[0]

arcpy.AddField_management(fc, "filename", "TEXT", "", "", 25)
arcpy.CalculateField_management(fc, "filename", tmp2)

But I got error saying "CalculateField_management" failed to execute. Is there any problem with the script? Thanks!

Re: add and calculate field

StacyRendall1 — Fri, 30 Sep 2011 05:32:59 GMT

What is fcname? You don't specify it before calling it. Although, that isn't directly related to your error.

You could try adding:

arcpy.AddMessage('%s' % tmp2)

just before your add field line, to check what tmp2 is actually coming out like before the calculation.

Re: add and calculate field

MarcNakleh — Fri, 30 Sep 2011 12:07:43 GMT

Hello,

If you're creating the textfield filename, and trying to write text to it, I think I see the problem.
For string literals, your expression value needs to be encapsulated by quotes when it's passed to the Field Calculator. Your code should therefore be:

arcpy.CalculateField_management(fc, "filename", '"' + tmp2 + '"')

What you were passing to the expression field before was this:

myfilename

whereas what you wanted to send, and what you'd see in the Field Calculator, is this:

"myfilename"

Hope this helps!

Re: add and calculate field

YinghaiKe — Fri, 30 Sep 2011 16:10:29 GMT

Thank you, mnakleh, that works great! Thanks!