In the attached screenshot, the attributes contain two field of interest "a" and "b". I want to write a script to access the adjacent rows in order to make some calculations. To access a single row, I would use the following UpdateCursor:
fc = r'C:\path\to\fc'
with arcpy.da.UpdateCursor(fc, ["a", "b"]) as cursor:
for row in cursor:
# Do something
For example, with OBJECTID 4, I am interested in calculating the sum of the row values in field "a" adjacent to OBJECTID 4 row (i.e. 1 + 3) and adding that value to the OBJECTID 4 row in the "b" field. How can I access adjacent rows with the cursor to make these sort of calculations?