Python Script to Add Multiple Fields to Feature Classes

Question

I am trying to add 2 (multiple) fields to each feature class in a gdb. I based the script off of Python Script to Add Fields to Feature Classes.

I feel like I am missing something and can't figure it out.

import arcpy, os

arcpy.env.workspace = r'Z:\project\....gdb'

for fc in arcpy.ListFeatureClasses():
    try:
        arcpy.AddField_management(fc, "Depth", "SHORT", field_length = 10)
        arcpy.AddField_management(fc, "OD", "SHORT", field_length = 10)
        with arcpy.da.UpdateCursor(fc, "Depth", "OD") as cursor:
            for row in cursor:
                row[0] = fc
                cursor.updateRow(row)
                print "Working on {0}".format(fc)

    except Exception as ex:
        print "There was an error --->    {0}".format(ex)

print ("Add Field Finished")

Answer 1

You need to put the fields you want to include in the cursor within a list or tuple. How you have it now, you are putting a WHERE clause of "OD".

arcpy.da.UpdateCursor(in_table, field_names, {where_clause}, {spatial_reference}, {explode_to_points}, {sql_clause})

You want:

with arcpy.da.UpdateCursor(fc, ("Depth", "OD")) as cursor:

With that said, I don't understand what you are trying to do with row[0] = fc

You're assigning the "DEPTH" field which is of integer data type a string value.

If you just want to add fields to each feature class, this part of your code should work:

import arcpy

arcpy.env.workspace = "Z:\\project\\....gdb"

for fc in arcpy.ListFeatureClasses():
    try:
        arcpy.AddField_management(fc, "Depth", "SHORT", field_length = 10)
        arcpy.AddField_management(fc, "OD", "SHORT", field_length = 10)

    except Exception as ex:
        print "There was an error --->    {0}".format(ex)

print("Add Field Finished")

Answer 2

I do this often without issue. The only difference between what I do, and what you're doing is I don't use the .da cursor. I use arcpy.UpdateCursor instead. So mine would look like:

import arcpy, os

arcpy.env.workspace = r'Z:\project\....gdb'

for fc in arcpy.ListFeatureClasses():
    try:
        arcpy.AddField_management(fc, "Depth", "SHORT", field_length = 10)
        arcpy.AddField_management(fc, "OD", "SHORT", field_length = 10)
        with arcpy.UpdateCursor(fc) as cursor:
            print "Working on {0}".format(fc)
            for row in cursor:
                row.FIELDNAMEHERE = fc #I am guessing you're assigning the name of the layer here?
                cursor.updateRow(row)


    except Exception as ex:
        print "There was an error --->    {0}".format(ex)

print ("Add Field Finished")

My usual way of implementing the code is:

layers = [#my list of layers here]
for layer in layers:
  arcpy.AddField_management(layer, "NEWFIELD", "TEXT")
  rows = arcpy.UpdateCursor(layer)
    for row in rows:
      row.NEWFIELD = "my new value"
      rows.updateRow(row)
  del rows