topic Re: Field Calculator — Sort values, grouped by GROUP_ID field in ArcGIS Pro Questions

Field Calculator — Sort values, partitioned by GROUP_ID field

Bud — Fri, 23 Aug 2024 01:25:59 GMT

ArcGIS Pro 3.3.1; file geodatabase

GROUP_ID VALUES 
1        0
1        1
1        0

2        0
2        0

3        1
3        0
3        1

I want to rearrange the VALUES data so that the values are sorted descending, sorted within each GROUP_ID partition.

GROUP_ID VALUES 
1        1
1        0
1        0

2        0
2        0

3        1
3        1
3        0

How can I do that using the Field Calculator?

I’m aware of the Sort geoprocessing tool. But I don’t want to use Sort because it outputs a separate FC. I want to update the original FC directly. And I would prefer not to use the Sort tool, join it back to the original FC, and then do a filed calculation to bring in the joined/sorted values.

I don’t want to sort the rows, I want to edit the values and leave the row order as-is.

Re: Field Calculator — Sort values, grouped by GROUP_ID field

JoshuaBixby — Thu, 22 Aug 2024 18:00:39 GMT

Why does it have to be Calculate Field? This is much more straight-forward with cursors.

Re: Field Calculator — Sort values, grouped by GROUP_ID field

Bud — Thu, 22 Aug 2024 18:31:51 GMT

I’m inexperienced with Python, so I assumed a field calculation would be easiest. I hadn’t considered a Python cursor script in the Python Window as an option. But if that’s easier, then it would be fine.

Re: Field Calculator — Sort values, grouped by GROUP_ID field

JoshuaBixby — Thu, 22 Aug 2024 19:06:12 GMT

With Calculate Field, there is no way to ensure row order, truly ensure it. So, doing order-dependent row operations is kludgy at best and generally error prone. With cursors, you can specify an ORDER BY statement to ensure row order, or you can loop through a cursor twice using a dictionary to store and update values. If someone else doesn't offer up some code, I will take a look in a day or so.