topic How Can I Set a Definition Query from a Selection in Arcpy? in ArcMap Questions

How Can I Set a Definition Query from a Selection in Arcpy?

rescobar — Fri, 06 Jan 2023 22:38:23 GMT

Hello, I am trying to get a script to set a definition query from a selection. The selection is set by using an intersect from a buffer layer. I know the first part works, because if I just run this, it will create a selection in the mxd. I have also tested the second 'for...' with an mxd open and it works. However, I need to run this with the mxd closed, as it is being newly created. All I get is "OBJECTID IN ()" in the county layer's query.

for lyr in arcpy.mapping.ListLayers (mxd,'HALF_MILE_BUFFER'): county_lyr = arcpy.mapping.ListLayers(mxd, 'County')[0] arcpy.SelectLayerByLocation_management(county_lyr,"INTERSECT",lyr) for lyr in arcpy.mapping.ListLayers (mxd,'County'): fids = arcpy.Describe(lyr).FIDSet idfield = 'OBJECTID' wc = idfield + ' IN (' + fids.replace(';',',') + ')' county_lyr.definitionQuery = wc arcpy.SelectLayerByAttribute_management(lyr, "CLEAR_SELECTION")

Re: How Can I Set a Definition Query from a Selection in Arcpy?

JohannesLindner — Mon, 09 Jan 2023 13:01:34 GMT

Can't test in ArcMap, but I saw the same behavior in ArcGIS Pro. I could solve it by creating a new layer in memory:

buffer_lyr = arcpy.mapping.ListLayers (mxd,'HALF_MILE_BUFFER')[0] # get the layer in the map county_lyr_in_map = arcpy.mapping.ListLayers(mxd, 'County')[0] # create a new layer using the map layer's data source county_lyr = arcpy.management.MakeFeatureLayer(county_lyr_in_map.dataSource, "SomeName") # select in that new layer arcpy.management.SelectLayerByLocation(county_lyr, "INTERSECT", buffer_lyr) # set the definition query in the map layer fids = arcpy.Describe(county_lyr).FIDSet county_lyr_in_map.definitionQuery = 'OBJECTID IN (' + fids.replace(';', ',') + ')'

Re: How Can I Set a Definition Query from a Selection in Arcpy?

rescobar — Mon, 09 Jan 2023 16:46:40 GMT

Thank you so much Johannes, this works! Hope you have a good week 🙂