I am trying to remove rows from a feature class that is included in a python tool in ArcGIS 10.7. I have run the code as an independent Python script and it runs fine, but when I run the following code, I get an error. tmpfile is a copy of an existing feature that is in a geodatabase.

tmpfile = os.path.basename(tempfile.TemporaryFile().name) 
arcpy.CopyFeatures_management(infile, tmpfile)

### remove unnecessary values
vals = ["Unknown",""]
for val in vals:
    query = """ "DATEDISC" = '%s' """ %val
    tmpfile = arcpy.SelectLayerByAttribute_management(tmpfile,"NEW_SELECTION", query)

In the standalone script, this removes any rows with the values of "Unknown" or "". In the tool, I receive the error message for arcpy.SelectLayerByAttribute_management() that

The value cannot be a feature class
ERROR 000840: The value is not a Raster Layer.
ERROR 000840: The value is not a Mosaic Layer.
Failed to execute (SelectLayerByAttribute).

This seems like odd behavior for this function.

Does anyone know why this would be happening?

  • 1
    We need to know what tmpfile is. How are you setting tmpfile or passing it into your tool?
    – KHibma
    Commented Jul 9, 2020 at 18:45
  • I edited the question. tmpfile is a feature class.
    – user44796
    Commented Jul 9, 2020 at 18:50

1 Answer 1


There are several problems with your code. You create a variable called tmpfile and then you overwrite it so destroying the original value. Your variable is a feature class. If you read the help file for the tool select by attribute you will see it takes as input a feature layer not a feature class. You need to convert your feature class into a layer first and feed that into the select tool.

  • 1
    You are correct. Also, you can't save the results into a new object. This is allowable in arcpy, but not in the toolbox. So tmpfile = arcpy.SelectLayerByAttribute_management(lyr,"NEW_SELECTION", query) needs to be replaced with arcpy.SelectLayerByAttribute_management(lyr,"NEW_SELECTION", query), where lyr is a layer file created from tmpfile
    – user44796
    Commented Jul 9, 2020 at 19:51

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