Using ArcPy to write feature class name to field in GDB?

Question

I have a file GDB living in a network directory with 17 or 18 feature classes. I already created a field I want to populate with the file name of the feature class. Whenever I run my code, it returns

NameError: name 'Washington_PETA' is not defined

This is presumably the first feature class it finds in the GDB. File path altered because there may be sensitive data in it.

Doing this in Python 3 because we're using ArcGIS Pro.

import arcpy, os, sys
arcpy.env.overwriteOutput = True
arcpy.env.workspace = r"R:\filePathHere\feature.gdb"
petas = arcpy.ListFeatureClasses()
for fc in petas:
 print("Updating " + fc)
 inField = "PETA_Name"
 fileName = os.path.basename(fc)
 arcpy.CalculateField_management(fc, inField, fileName, "PYTHON3")
 print(fc + " completed")

• Andy: Welcome to GIS SE! As a new user, please be sure to take the short tour to learn about this site's focused Q&A format.
• Bera: You dont need to use os.path.basename(fc) since fc will be the name of a feature class without the path, so fileName=fc

Answer 1

The Field Calculator expects a quoted string in its expression parameter if you are supplying a simple text string. You can concatenate a pair of double quotes like so: '"' + fileName + '"'.

Your full script would be:

import arcpy, os, sys
arcpy.env.overwriteOutput = True
arcpy.env.workspace = r"R:\filePathHere\feature.gdb"
petas = arcpy.ListFeatureClasses()
for fc in petas:
 print("Updating " + fc)
 inField = "PETA_Name"
 fileName = os.path.basename(fc)
 arcpy.CalculateField_management(fc, inField, '"' + fileName + '"', "PYTHON3")
 print(fc + " completed")

• Bera: Or "'{0}'".format(fileName)