I've been trying to create a python script that will update certain fields in the arcgis attribute table. I have attempted to do this by using the update cursor to update a field based on another field value found in the same row.

Here is the code I used:

import arcpy

fc = "C:\Users\maureen\Documents\ArcGIS\EDRN\EDRN_LINK.shp"
fields = ["FID", "RIVERNAME"]

with arcpy.da.UpdateCursor(fc, fields) as cursor:
    for row in cursor:
        if  row[0] = 4401:
            row[1] = "Aire"

Unfortunately, when I run this in ArcMap it returns the following syntax error:

Parsing error SyntaxError: invalid syntax (line 9) 

Does anyone have any idea where I'm going wrong? I've researched this script a fair bit and can't see any obvious errors.

  • I suppose you ment if row[0] == 4401: // ... You forgot the double-equal-sign, that´s it I think Commented Jun 20, 2014 at 14:49
  • In addition to the answers below, make sure the "RIVERNAME" field is a text field.
    – Aaron
    Commented Jun 20, 2014 at 15:07
  • from @Aaron above - I run into Subtypes sometimes and bang my head on the wall until I realize I'm looking for an integer value. The == is the main problem though.
    – gm70560
    Commented Jun 21, 2014 at 3:36

1 Answer 1


For comparison of 'equals' you need to use a double equals sign '=='

if  row[0] == 4401:
        row[1] = "Aire"

A single equals sign is the assignment operator in python.

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