Arcpy UpdateCursor – How to Use UpdateCursor to Update a Field Based on Other Field Values in ArcGIS

Question

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"
            cursor.updateRow(row)

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.

Answer 1

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

if  row[0] == 4401:
        row[1] = "Aire"
        cursor.updateRow(row)

A single equals sign is the assignment operator in python.