arcpy - Python Script to Add Fields to Feature Classes

I have to try to add a field called 'Name' to a bunch of different feature classes using python, and then access the name of the feature class to fill in the field. I have no idea how to even start this! I know I need a loop but that's all I know.

Answer

Here is a cursor-based approach, which I usually default to as syntax is simpler than using Calculate Field. This is the workflow:

import your module

import arcpy

Set the workspace so that Python knows where to look for the feature classes. In this case, it is a GDB

arcpy.env.workspace = r'C:\temp2\my_gdb.gdb'

Start a loop and iterate over the feature classes in the GDB

for fc in arcpy.ListFeatureClasses():

Add a text field called "Name" of length 50

arcpy.AddField_management(fc, "Name", "TEXT", field_length = 50)

Within each feature class attribute table, write the name of the current FC

with arcpy.da.UpdateCursor(fc, "Name") as cursor:
    for row in cursor:
        row[0] = fc
        cursor.updateRow(row)

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import arcpy

arcpy.env.workspace = r'C:\temp2\my_gdb.gdb'


for fc in arcpy.ListFeatureClasses():
    arcpy.AddField_management(fc, "Name", "TEXT", field_length = 50)
    with arcpy.da.UpdateCursor(fc, "Name") as cursor:
        for row in cursor:
            row[0] = fc
            cursor.updateRow(row)

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