ArcMap

Select Layer By Attribute

Summary

Adds, updates, or removes a selection on a layer or table view based on an attribute query.

Usage

  • The input must be a feature layer or a table view. The input cannot be a feature class or table.

  • This tool works on layers or table views in the ArcMap table of contents, and also on layers or table views created in a scripts using the Make Feature Layer or Make Table View tools.

  • If an Extent environment is specified, or if a definition query is present on the Input Layer or Table View, only the features or rows within the extent or matching the definition query may be selected.

  • The Get Count tool can be used to determine the number of features or rows selected. This can be especially useful in a script or model to determine if further processing is desired.

Syntax

arcpy.management.SelectLayerByAttribute(in_layer_or_view, {selection_type}, {where_clause})
ParameterExplanationData Type
in_layer_or_view

The feature layer or table view to which the selection will be applied.

The input can be a layer or table view in the ArcMap table of contents, or a layer or table view created in ArcCatalog or in scripts using the Make Feature Layer or Make Table View tools.

Table View; Raster Layer; Mosaic Layer
selection_type
(Optional)

Determines how the selection will be applied and what to do if a selection already exists.

  • NEW_SELECTION —The resulting selection replaces any existing selection. This is the default.
  • ADD_TO_SELECTION —The resulting selection is added to an existing selection if one exists. If no selection exists, this is the same as the NEW_SELECTION option.
  • REMOVE_FROM_SELECTION —The resulting selection is removed from an existing selection. If no selection exists, this option has no effect.
  • SUBSET_SELECTION —The resulting selection is combined with the existing selection. Only records that are common to both remain selected.
  • SWITCH_SELECTION —Switches the selection. All records that were selected are removed from the selection; all records that were not selected are added to the selection. The Expression is ignored when this option is specified.
  • CLEAR_SELECTION —Clears or removes any selection. The Expression is ignored when this option is specified.
String
where_clause
(Optional)

An SQL expression used to select a subset of records. For more information on SQL syntax see the help topic SQL reference for query expressions used in ArcGIS.

SQL Expression

Derived Output

NameExplanationData Type
out_layer_or_view

The updated input with selection applied.

Table View; Raster Layer; Mosaic Layer

Code sample

SelectLayerByAttribute example 1 (Python window)

The following Python window script demonstrates how to use the SelectLayerByAttribute function in immediate mode.

import arcpy
arcpy.MakeFeatureLayer_management("C:/data/data.mdb/states", "stateslyr")
arcpy.SelectLayerByAttribute_management("stateslyr", "NEW_SELECTION", " [NAME] = 'California' ")
SelectLayerByAttribute example 2 (stand-alone script)

The following stand-alone script shows how to use the SelectLayerByAttributes function in a workflow to extract features to a new feature class based on location and an attribute query.

# Name: ExtactFeaturesByLocationAndAttribute.py
# Description: Extract features to a new feature class based on a spatial relationships to another layer AND an attribute query
 
# Import system modules
import arcpy

# Set the workspace
env.workspace = "c:/data/mexico.gdb"

# Make a layer from the feature class
arcpy.MakeFeatureLayer_management("cities", "lyr") 
 
# Select all cities which overlap the chihuahua polygon
arcpy.SelectLayerByLocation_management("lyr", "intersect", "chihuahua", 0, "new_selection")

# Within selected features, further select only those cities which have a population > 10,000   
arcpy.SelectLayerByAttribute_management("lyr", "SUBSET_SELECTION", ' "population" > 10000 ')
 
# Write the selected features to a new featureclass
arcpy.CopyFeatures_management("lyr", "chihuahua_10000plus")

Environments

Licensing information

  • Basic: Yes
  • Standard: Yes
  • Advanced: Yes

Related topics