topic Not Able to Pass Where Clause in SearchCursor in ArcPy in Python Snippets Questions

Not Able to Pass Where Clause in SearchCursor in ArcPy

BehrouzHosseini — Sun, 12 Dec 2021 09:38:03 GMT

Can you please take a look at this snippet and let me know why I am not able to properly pass the Where Clause ('"[NAME_1]" = Ohio') in SearchCursor?

import arcpy
from arcpy import env
def unique_values(table , field):
 with arcpy.da.SearchCursor(table, [field], '"[NAME_1]" = Ohio') as cursor:
 return sorted({row[0] for row in cursor})
uniques = unique_values(r'C:\arcgis\ArcTutor\AAA\src\USA.shp' , 'NAME_2')
for unique in uniques:
  print (unique)‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

I am getting this error on runtime

Traceback (most recent call last):
File "<module1>", line 8, in <module>
File "<module1>", line 7, in unique_values
File "<module1>", line 7, in <setcomp>
RuntimeError: Unspecified error

Same error on this format as well

with arcpy.da.SearchCursor(table, [field], '"NAME_1" = Ohio') as cursor:

Re: Not Able to Pass Where Clause in SearchCursor in ArcPy

curtvprice — Tue, 16 Oct 2018 04:34:20 GMT

This syntax is incorrect for shape file query expressions. The bracket delimeter you are using on the field name "[field]" is only used for personal geodatabases (.mdb), which BTW are not supported in 64-bit arcpy (Desktop background processing or ArcGIS Pro). Text literals also need to be surrounded by quotes.

'"NAME_1" = \'Ohio\''‍

There are some other issues with your code but we should probably start with that.

Re: Not Able to Pass Where Clause in SearchCursor in ArcPy

BehrouzHosseini — Tue, 16 Oct 2018 04:48:21 GMT

Thanks Curtis, the code is working now but can you please let me know what are the other issues which you noticed them?

Re: Not Able to Pass Where Clause in SearchCursor in ArcPy

BrittneyWhite1 — Tue, 16 Oct 2018 17:32:00 GMT

I'll add that if you don't want to memorize the delimeters for each data type, you can always use the AddFieldDelimiters function:

See the section in the Specifying a query in Python help page: http://pro.arcgis.com/en/pro-app/arcpy/get-started/specifying-a-query.htm#GUID-98106084-6ECE-4647-A50D-50EF0B46EC25

Re: Not Able to Pass Where Clause in SearchCursor in ArcPy

curtvprice — Wed, 17 Oct 2018 03:15:03 GMT

I took another look at your code and it seems to look okay. One thing I've done to unique-ize the list is to use list(set(mylist)) but your method of using a dictionary ({}) is pretty neat and is probably very fast!