topic Re: Select Layer by Attribute issues in Python Questions

Select Layer by Attribute issues

ShelbyHines — Tue, 24 Oct 2017 05:08:08 GMT

Hi all,

I am trying to 1) Select by Attribute and 2) overwrite a feature class with selected features. Below is the script that I'm trying as a start.. and am getting an error related to Select by Attribute. Ultimately, need to select last 365 days of data (not Baker neighborhood) and overwrite a feature class.. on a daily basis. Thank you in advance for any assistance! Shelby

# Description: Extract features to a new feature class based on an attribute query
# Import system modules
import arcpy

# Make a layer from the feature class
arcpy.MakeFeatureLayer_management ("D:/pd/crimeD.gdb/dencrime", "crimelayer")

# Select all crimes that happened in Baker
arcpy.SelectLayerByAttribute_management ("crimelayer", "NEW_SELECTION", ' "NEIGHBORHOOD_ID" = baker ')
# Write the selected features to a new featureclass
arcpy.CopyFeatures_management("crimelayer", "Bakercrime")

Re: Select Layer by Attribute issues

DanPatterson_Retired — Tue, 24 Oct 2017 08:34:44 GMT

With the shell script what is the error just in case

there is an error in the script and more importantly
it wouldn't work in the first place because what you are querying doesn't exist

Secondly...

how is the time data stored?
is it in a field?
sequential values?
is it a date field or a string field?

More questions pending the answers to the above.

Re: Select Layer by Attribute issues

ShelbyHines — Tue, 24 Oct 2017 13:08:25 GMT

Thank you Dan!

This is the error that I'm getting:

Traceback (most recent call last):
File "<string>", line 7, in <module>
File "c:\program files\arcgis\pro\Resources\arcpy\arcpy\management.py", line 6569, in SelectLayerByAttribute
raise e
File "c:\program files\arcgis\pro\Resources\arcpy\arcpy\management.py", line 6566, in SelectLayerByAttribute
retval = convertArcObjectToPythonObject(gp.SelectLayerByAttribute_management(*gp_fixargs((in_layer_or_view, selection_type, where_clause, invert_where_clause), True)))
File "c:\program files\arcgis\pro\Resources\arcpy\arcpy\geoprocessing\_base.py", line 506, in <lambda>
return lambda *args: val(*gp_fixargs(args, True))
arcgisscripting.ExecuteError: ERROR 000358: Invalid expression
Failed to execute (SelectLayerByAttribute).

Regarding your other questions, the date is in a field and is "date" data type. Yes, they are sequential dates from 2010 through today. Hundreds per day.

Much appreciated, Shelby

Re: Select Layer by Attribute issues

XanderBakker — Tue, 24 Oct 2017 13:18:36 GMT

It is likely the query you are using. the value Baker should be between quotes and the field name (if FC is stored in fgdb) would be without quotes. Something like this:

arcpy.SelectLayerByAttribute_management ("crimelayer", "NEW_SELECTION", "NEIGHBORHOOD_ID = 'baker'")

Sorry no access to my computer at this time to verify a little more.

Re: Select Layer by Attribute issues

ShelbyHines — Tue, 24 Oct 2017 17:58:41 GMT

Thank you Xander, this worked!

Re: Select Layer by Attribute issues

ShelbyHines — Tue, 24 Oct 2017 17:59:50 GMT

Hi Dan_Patterson, I wonder if you know how to query for data from the last 365 days using a date field? Thank you! -Shelby

Re: Select Layer by Attribute issues

DanPatterson_Retired — Sat, 11 Dec 2021 14:12:12 GMT

import datetime

n = datetime.datetime.now()  # ---- now 

t = datetime.timedelta(days=365)  # ---- used timedelta options 

print("Now  {} \nThen {}".format(n, n-t))

Now  2017-10-24 15:05:40.710201 
Then 2016-10-24 15:05:40.710201

# ---- see the help for working with arcpy time objects‍‍‍‍‍‍‍‍‍‍‍‍

Shelby.... To give you some ideas

Re: Select Layer by Attribute issues

ShelbyHines — Tue, 24 Oct 2017 19:38:26 GMT

Thank you for this, will be testing this! Was able to make it work with the help of a colleague:

arcpy.SelectLayerByAttribute_management("crimelayer", "NEW_SELECTION", "REPORTED_DATE > timestamp '{0}'".format(str(year_ago)), None)