topic Re: UpdateCursor in Python Questions

UpdateCursor

stewart — Wed, 01 Nov 2023 10:42:05 GMT

I am trying to update my attribute field based on a dictionary (join_count_dict) containing {FID:Join_Count}, (eg. {0:1,2:3,3:0,...}
The shapefile has an equal amount of FID as the dictionary, my script works occassionally, any suggestions?

with arcpy.da.UpdateCursor(shapefile, ['FID','Join_Count']) as cursor:

for row in cursor:
FID=row[0]
if FID in join_count_dict:
row[0] += join_count_dict[fid]
cursor.updateRow(row)

Any help is much appreciated!

Re: UpdateCursor

stewart — Wed, 01 Nov 2023 11:33:06 GMT

should it rather be

with arcpy.da.UpdateCursor(shapefile, ['FID','Join_Count']) as cursor:

for row in cursor:
FID=row[0]
if FID in join_count_dict:
row[1] += join_count_dict[fid]
else:
row[1] = -1
cursor.updateRow(row)
cursor.updateRow(row)

Re: UpdateCursor

BlakeTerhune — Wed, 01 Nov 2023 15:57:59 GMT

This should technically work, but you have an extra line calling updateRow() that should be removed. I don't know if the logic is what you want to happen though. Can you clarify exactly what happens when it doesn't work? Is there an error message?

Re: UpdateCursor

VinceAngelo — Fri, 03 Nov 2023 15:37:34 GMT

Please put your code in code blocks (click on Post options, choose "Edit post (or reply)", hit the "..." in the top-right of the editor menu (to expand the menu block), copy the code text, then click on "</>" and paste into the popup, then clean up the code inside and outside the code block). This will make your code legible.

- V

Re: UpdateCursor

stewart — Fri, 03 Nov 2023 12:38:17 GMT

There is something else that was ruining it, the extra line is due my poor abilities on posting here. Thanks for the attention though, much appreciated.

Re: UpdateCursor

StaticK — Sun, 05 Nov 2023 12:46:58 GMT

Is fid declared anywhere? I see FID, but python is case sensitive so what is fid in join_count_dict[fid]?