topic Re: Pass dictionary key to arcpy.SelectLayerByAttribute_management in Python Questions

Pass dictionary key to arcpy.SelectLayerByAttribute_management

TonyAlmeida — Fri, 11 Jun 2021 16:19:39 GMT

I am trying to compare the PIN fields of two layers, fc1 and fc2 and select fc2 features. The issues I have is that this process one PIN at a time it doesn't just select them all at once.

#arcpy.MakeFeatureLayer_management(fc2, "fc2_Lyr") for WellID in fc2List: arcpy.SelectLayerByAttribute_management(fc2, "NEW_SELECTION", "\"PIN\" = '{}'".format(WellID)) #arcpy.MakeFeatureLayer_management(fc2, "SelPar_lyr", "\"PIN\" = '{}'".format(WellID))

Re: Pass dictionary key to arcpy.SelectLayerByAttribute_management

DavidPike — Fri, 11 Jun 2021 16:01:01 GMT

Not entirely sure what you mean, is it to select everything in fc2list?

If so, maybe just get rid of the for loop and use the SQL 'IN' statement.

arcpy.SelectLayerByAttribute_management("fc2_Lyr", "NEW_SELECTION", "\"PIN\" IN ({})".format(fc2List))

Re: Pass dictionary key to arcpy.SelectLayerByAttribute_management

TonyAlmeida — Fri, 11 Jun 2021 16:20:25 GMT

My bad I thought I posted the whole code.

fc = "Wells" fc2 = "Polygon" fcList = [] fc2List = [] with arcpy.da.SearchCursor(fc, ["PIN"]) as cursor: for row in cursor: fcList.append(row[0]) #print row[0] with arcpy.da.SearchCursor(fc2, ["PIN"]) as cursor: for row in cursor: if row[0] in fcList: fc2List.append(row[0]) print row[0] #arcpy.MakeFeatureLayer_management(fc2, "fc2_Lyr") for WellID in fc2List: arcpy.SelectLayerByAttribute_management("fc2, "NEW_SELECTION", "\"PIN\" = '{}'".format(WellID)) #arcpy.MakeFeatureLayer_management(fc2, "SelPar_lyr", "\"PIN\" = '{}'".format(WellID))

Re: Pass dictionary key to arcpy.SelectLayerByAttribute_management

JoeBorgione — Fri, 11 Jun 2021 17:09:31 GMT

A variation on @DavidPike 's theme. Here I use list comprehension to create a list of the Wells pin values and then select the Polygons if the PIN is in the list. You mentioned using a dictionary in the subject and you can use dictionary comphrension the same way. FYI: untested. you may need to fiddle with the select statement...

import arcpy fc = "Wells" fc2 = "Polygon" fields = ['PIN'] fcList = [i[0] for i in arcpy.da.SearchCursor(fc,fields)] arcpy.MakeFeatureLayer_management(fc2, "fc2_Lyr") select = f'PIN IN {list}' arcpy.SelectLayerByAttribute_management("fc2_Lyr", 'ADD_TO_SELECTION', select)

Re: Pass dictionary key to arcpy.SelectLayerByAttribute_management

BlakeTerhune — Fri, 11 Jun 2021 17:36:47 GMT

I like this, but don't forget that formatting your select string with the list isn't valid SQL syntax because of the brackets. You need to reformat it with parenthesis. Assuming PIN is a string, you would need

select = f'PIN IN({",".join(fcList)})'

Re: Pass dictionary key to arcpy.SelectLayerByAttribute_management

JoeBorgione — Fri, 11 Jun 2021 17:39:27 GMT

Thanks @BlakeTerhune That's exactly why I included the disclaimer!

Re: Pass dictionary key to arcpy.SelectLayerByAttribute_management

TonyAlmeida — Fri, 11 Jun 2021 19:09:23 GMT

ok, thanks for the suggestion. It is not liking the expression. This is currently in a shapefile.
Failed to execute (SelectLayerByAttribute). PIN is a string

arcpy.MakeFeatureLayer_management(fc2, "fc2_Lyr") result = arcpy.GetCount_management("fc2_Lyr").getOutput(0) print ('{} has {} records'.format("fc2_Lyr", result[0])) select = f'PIN IN({",".join(fc2List)})' arcpy.SelectLayerByAttribute_management("fc2_Lyr", 'ADD_TO_SELECTION', select)

Re: Pass dictionary key to arcpy.SelectLayerByAttribute_management

JoeBorgione — Fri, 11 Jun 2021 19:29:24 GMT

pinList = ['123','456','789'] '123' in pinList Out[2]: True '123' in ','.join(pinList) Out[4]: True

Like I said, you'll need to fiddle a bit with the selection statement. It typically takes me a time or two to get them right,

Re: Pass dictionary key to arcpy.SelectLayerByAttribute_management

BlakeTerhune — Fri, 11 Jun 2021 20:41:58 GMT

Ah, I forgot the single quotes. As @JoeBorgione mentioned, these often take some fiddling. Hopefully this will keep the strings as single quotes.

select = f"PIN IN({str(fc2List)[1:-1]})"

Edit:

I just found this solution that is more robust and less of a hack.

str_values = ",".join(f"'{x}'" for x in fc2List) select = f"PIN IN({str_values})"

Re: Pass dictionary key to arcpy.SelectLayerByAttribute_management

DanPatterson — Sat, 12 Jun 2021 03:04:41 GMT

Geoprocessing considerations for shapefile output—ArcGIS Pro | Documentation

dBASE files have little SQL support aside from a WHERE clause.