Getting 999999 error from ArcPy script to increment one field when another field contains 0?

Question

Before I begin I should emphasise that my python knowledge is pretty limited; generally self taught or inspired by snippets I have found on here.

I have a .dbf table, and I need to use python to increment values (row above + 1) in a field ONLY when a value in another field is 0. For all other rows the value is 1. To better illustrate this, when it is complete the table should look something like this:

FID   Value   Increment
 0      1        0
 1      1        0
 2      1        0
 3      1        0
 4      0        1
 5      0        2
 6      0        3
 7      0        4
 8      1        4
 9      1        4
 10     1        4
 11     1        4
 12     0        5

Using the code from the top answer to Computing new attribute based on changes in another attribute using ArcGIS Desktop with Python?

I edited the code to look like this:

import arcpy

fc = arcpy.GetParameterAsText(0)

rows = arcpy.UpdateCursor(fc)

increment = 0
for row in rows:
    if row.VALUE == 0:
        increment += 1
        row.INCREMENT = increment
        rows.updateRow(row)

    while row.VALUE == 1:
        row.INCREMENT = increment
        rows.updateRow(row)
        rows.next()

    row.INCREMENT = increment
    rows.updateRow(row)

del row, rows

I run it, and it takes quite a while (I have about 11,000 records in the table), before I get this error:

Traceback (most recent call last):
  File "C:\scratch\incrementLine_IncreFieldEverytimeIncrementChanges.py", line 16, in <module>
    rows.updateRow(row)
  File "c:\program files (x86)\arcgis\desktop10.1\arcpy\arcpy\arcobjects\arcobjects.py", line 102, in updateRow
    return convertArcObjectToPythonObject(self._arc_object.UpdateRow(*gp_fixargs(args)))
RuntimeError: ERROR 999999: Error executing function.

The thing is though, the code DOES work, it gives me the result in the table that I want, but due to this error I can't slot this script into my ModelBuilder flow, which is rather frustrating!

So my question is, what is causing this error? As I said, the script is editing the table how I want it, so if there is way I can just stop the error so I can use it in a flow that would be ideal! I imagine my limited knowledge in python (and scripting in general) is making me miss something entirely obvious, and also the fact that I'm basically ripping off a script from 2012 could be introducing out of date techniques?

Answer 1

You could try this:

import arcpy

fc = arcpy.GetParameterAsText(0)

rows = arcpy.UpdateCursor(fc)

increment = 0
for row in rows:
    if row.VALUE == 0:
        increment += 1

    row.INCREMENT = increment
    rows.updateRow(row)

del row, rows