Help with ArcGIS10 Python and SearchCursor reading Null values in field

Question

I'm using a Phython script to count the number of unique string values in a feature class. My script works if there are values in the field but if there are any NUll values in the field it crashes. Any Ideas?

import arcpy
import operator

inTable = arcpy.GetParameterAsText(0)
stringField = arcpy.GetParameterAsText(1)


stringList = [row.getValue(stringField) for row in arcpy.SearchCursor
                                       (inTable, "", "",stringField)]

Answer 1

Use isNull(field_name) method before getting values. For further info see this help topic

Answer 2

Null values are equal to the python None so you could also handle null values like this

if row.getValue(stringField) == None: do something if row.getValue(stringField) != None: do something else