Selection within Nested Loop Not Working as Expected

ssintelmann — Tue, 15 Mar 2022 18:42:51 GMT

Thought this was fixed yesterday, mistaken. I have two sets of polygons. One featureclass has different fields for YEAR (integer), and GEAR type (string). I am trying to loop through each of these two fields and do an Identity with the other polygon. Output I am looking for will ONLY contain the polygons for each year and gear combination. The code seems to run without error, but I get the exact same number of records for each identity output, so the selection within the loop clearly is not working right. I am using a function to get the unique values for the year and gear fields. Wondering what I am messing up?

import arcpy #Set the data environment arcpy.env.overwriteOutput = True arcpy.env.workspace = r'C:\Data\working\AK_Fishing_VMS\2021_Delivery\ArcPro_proj\ArcPro_proj.gdb' trawlBuffs = r'C:\Data\working\AK_Fishing_VMS\2021_Delivery\ArcPro_proj\ArcPro_proj.gdb\buffers\trawl_buffers' fishnet = r'C:\Data\working\AK_Fishing_VMS\2021_Delivery\ArcPro_proj\ArcPro_proj.gdb\fishnets\vms_net1k' spidentityOut = r'C:\Data\working\AK_Fishing_VMS\2021_Delivery\ArcPro_proj\ArcPro_proj.gdb\sp_identity\fishnet_' # function to list unique values of a field within a fc def unique_values(table, field): with arcpy.da.SearchCursor(table, [field]) as cursor: return sorted({row[0] for row in cursor}) del cursor # Get the list of values for the YEAR' field within the 'trawl_buffs' fc and place into a set yearVals = unique_values(trawlBuffs, "YEAR") unique_year = set(yearVals) # Get the list of values for the 'AGENCY_GEAR' field within the 'trawl_buffs' fc and place into a set gearVals = unique_values(trawlBuffs, "AGENCY_GEAR") unique_gear = set(gearVals) #loop through the years/gears with a selectionClause, and do the identity try: for year in unique_year: for gear in unique_gear: new_layer = str(year) + str(gear) arcpy.MakeFeatureLayer_management(trawlBuffs, new_layer) selectionClause = '{0} = {1}'.format('YEAR', year) + str(" AND ") + '{0} = '"'{1}'"''.format('AGENCY_GEAR',gear) arcpy.SelectLayerByAttribute_management(new_layer, "NEW_SELECTION", selectionClause) out_feat = spidentityOut + str(year) + str(gear) arcpy.Identity_analysis(trawlBuffs, fishnet, out_feat) print("Writing Data File: " + out_feat) # Drop unnecessary Fields dropFields = ['FID_vms_net1k'] arcpy.DeleteField_management(out_feat, dropFields) except Exception as e: #dump errors print("Error: " + e.args[0]) finally: #Clean up the temp layer arcpy.Delete_management(new_layer)

Re: Selection within Nested Loop Not Working as Expected

DavidPike — Tue, 15 Mar 2022 19:16:58 GMT

Maybe I'm missing something but you've applied a selection to new_layer then not done anything with it after.

#arcpy.Identity_analysis(trawlBuffs, fishnet, out_feat) #do you mean? arcpy.Identity_analysis(new_layer, fishnet, out_feat)

Re: Selection within Nested Loop Not Working as Expected

ssintelmann — Tue, 15 Mar 2022 19:29:47 GMT

No, you are absolutely correct! sigh. but relief, i need a walk now. Thanks yet again.

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Selection within Nested Loop Not Working as Expected

Re: Selection within Nested Loop Not Working as Expected

Re: Selection within Nested Loop Not Working as Expected