Is it possible to sort an arcpy.da.UpdateCursor()

Question

I have an arcpy data access update cursor that I would like to sort before making updates to. The cursor makes updates if I don't sort but if I add a sort to the cursor I get an error, "iteration not started."

The sort is working correctly but it must be busting the cursor for some reason.

Is it not possible to sort an update cursor like a search cursor? Does it change the type or something?

Thanks

    idList = ['100100', '100200', '100300', 200100']
    count = 0
    with arcpy.da.UpdateCursor(newFC, ("SHAPE@X", "SHAPE@Y", "Label")) as addLabelCursor:            
        for row in sorted(addLabelCursor, key=itemgetter(0), reverse = True): 
            print idList[count]
            row[2] = str(idList[count])
            addLabelCursor.updateRow(row)
            count += 1

Answer 1

The sort completely exhausts the cursor before you go into updateRow. The way that cursors work is that the updateRow call doesn't work on arbitrary rows out-of-seqence, but on the current one being iterated over. That is, you can only operate on one row at a time.

You may want to look into doing this on the geodatabase side instead. You can specify an ORDER BY clause and sort it before you get to it instead.