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I am new to Python, so sorry for such a trivial question. There is a shapefile (let's call it Structures.shp) and the script I'm writing needs to update the value of only one record in only one field (let's call the field structuretype). The field is the subtype field and the default value is (for example) 3, but the script needs to change the value for this particular record to 4. What is the easiest way for the script to update the value of this one cell?

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Thanks everyone! I totally forgot about cursors. I tried updating the table this way, and it worked. – Mhoram May 13 '13 at 17:15
up vote 10 down vote accepted

This should do it and is a little simpler than the examples in the online help for UpdateCursor which is nevertheless worth a read.

I've assumed your shapefile is in a folder called C:\temp and that structuretype is an integer field. If it is a text field just use "3" and "4" instead of 3 and 4.

import arcpy

features = arcpy.UpdateCursor(r"C:\temp\Structures.shp")
for feature in features:
    if feature.structuretype == 3:
        feature.structuretype = 4
del feature,features
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Thanks! I'll try it soon. – Mhoram May 11 '13 at 20:32
We need to thank @JasonScheirer for adding in an updateRow call - I should have tested rather than just written the code. – PolyGeo May 12 '13 at 10:16

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