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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

This does not alter any of the null values.

I'm using ArcGIS Desktop 10.0.

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up vote 9 down vote accepted

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

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

print "Processing complete"

del row
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