Using ArcPy update cursor to replace value?

Question

I have been combing the help associated with (None) values in arc, and have not been able to solve the following problem:

I have a a field with mixed Null and integer values:

0

100

I would like to transform the null values to 0's in python:

   cursor = arcpy.UpdateCursor(fishJoin, ['myField']):

    for row in cursor:
        if row is None:
            row = 0
            cursor.updateRow(row)

This does not alter any of the null values.

I'm using ArcGIS Desktop 10.0.

Answer 1

I would recommend using the data access module da with the Update Cursor as you will notice significant performance improvements. The following is the correct syntax to replace <Null> (aka None) values with 0.

import arcpy

fc = r'C:\path\to\your\FGDB.gdb\andFC'

with arcpy.da.UpdateCursor(fc, ["Field_Name"]) as cursor:
    for row in cursor:
        if row[0] == None:
            row[0] = 0
            cursor.updateRow(row)

print "Processing complete"

---

The following is the correct syntax for ArcGIS 10.0 (i.e. without the da module).

import arcpy

fc = r'C:\path\to\your\FGDB.gdb\andFC'

cursor = arcpy.UpdateCursor(fc)

for row in cursor:
    if row.YourFieldName == None:
        row.YourFieldName = 0
        cursor.updateRow(row)

print "Processing complete"

del row