topic Re: Using a Value from a list in a Query Clause in Python Questions

Using a Value from a list in a Query Clause

MikeEdwards — Tue, 17 Oct 2017 15:33:06 GMT

Hello,

I'm trying to export the errors from a Topology Validation. Multiple features are being validated at once and right now the output is three feature classes (poly, line, point) containing the errors from every feature class that has been validated.

I'm trying to change the export to be one for each feature class geometry type combination (stripping out the errors from each individual feature class and exporting them as their own.

What I have right now keeps ending with an Invalid Expression error (ExecuteError: ERROR 000358: Invalid expression
Failed to execute (SelectLayerByAttribute).).

Can anyone give me a hand figuring out what I'm doing wrong?

import arcpy
from arcpy import env

arcpy.env.overwriteOutput = True

env.workspace = "C:\Temp\Test_Data.gdb"

table = r"C:\Temp\Test_Data.gdb\TOPOLOGY\ArcGIS_Errors_line"
field = "OriginObjectClassName"

with arcpy.da.SearchCursor(table, field) as cursor:
   myValues_List = sorted({row[0] for row in cursor})
   for FeatureClassValue in myValues_List:
      queryClause = '"' + 'OriginObjectClassName = ' + "'" + FeatureClassValue.strip('\n') + "'" + '"'
      arcpy.MakeFeatureLayer_management("TC:\Temp\Test_Data.gdb\TOPOLOGY\ArcGIS_Errors_line","FEATURE_SELECTION")
      arcpy.SelectLayerByAttribute_management("FEATURE_SELECTION", "NEW_SELECTION", queryClause)
      arcpy.CopyFeatures_management("FEATURE_SELECTION", env.workspace + FeatureClassValue + "_Errors")

Re: Using a Value from a list in a Query Clause

MitchHolley1 — Tue, 17 Oct 2017 17:24:18 GMT

Have you tried printing the query to verify the syntax? If so, what does it look like?

Re: Using a Value from a list in a Query Clause

MikeEdwards — Tue, 17 Oct 2017 17:29:10 GMT

Printing the query gives me:

"OriginObjectClassName = 'BUILDINGS'"
"OriginObjectClassName = 'PARKS'"
"OriginObjectClassName = 'ROADS'"

If I substitute any of those with queryClause it works fine for that one feature.

Re: Using a Value from a list in a Query Clause

XanderBakker — Tue, 17 Oct 2017 17:32:06 GMT

Your query contains additional double quotes that shouldn't be there. Try this instead:

queryClause = "OriginObjectClassName = '{0}'".format(FeatureClassValue)‍

The other thing that I am wondering... is there really an enter after the featureclass name?

Re: Using a Value from a list in a Query Clause

MitchHolley1 — Sat, 11 Dec 2021 11:54:20 GMT

Try putting an 'r' in front of all paths. Check below

#what you have
arcpy.MakeFeatureLayer_management("TC:\Temp\Test_Data.gdb\TOPOLOGY\ArcGIS_Errors_line","FEATURE_SELECTION")

#what I think it should be
arcpy.MakeFeatureLayer_management(r"C:\Temp\Test_Data.gdb\TOPOLOGY\ArcGIS_Errors_line","FEATURE_SELECTION")‍‍‍‍‍‍‍‍

Re: Using a Value from a list in a Query Clause

MikeEdwards — Tue, 17 Oct 2017 17:36:45 GMT

Thanks guys, I'll give that a shot.

The TC:\ was a typo, I was just shortening the path names for posting on here.

Re: Using a Value from a list in a Query Clause

XanderBakker — Tue, 17 Oct 2017 17:47:41 GMT

It may have been a typo, but the comment made by mitchh300 still is valid. Your \T will convert into a TAB and create an invalid path. Please read this blog by Dan_Patterson : /blogs/dan_patterson/2016/08/14/filenames-and-file-paths-in-python

Re: Using a Value from a list in a Query Clause

MikeEdwards — Tue, 17 Oct 2017 17:48:25 GMT

That worked!

Thank you very much to both of you.

Re: Using a Value from a list in a Query Clause

XanderBakker — Tue, 17 Oct 2017 17:53:53 GMT

Great that worked. If it was the suggestion made by mitchh300 that helped you resolve the problem, could you mark his comment as the correct answer?