topic Re: Arcpy query data and switch selection in Python Questions

Arcpy query data and switch selection

JoseSanchez — Thu, 04 Mar 2021 20:38:35 GMT

Hello everyone

Its looks like these two cases produce the same results:

querySAOall = populated with a condition

# Make feature layer from my input data
arcpy.MakeFeatureLayer_management(inSAO, "LayerAll")

# Select by attribute and switch the selection
arcpy.SelectLayerByAttribute_management ("LayerAll", "NEW_SELECTION", querySAOall)
arcpy.SelectLayerByAttribute_management ("LayerAll", "SWITCH_SELECTION")

or:

# Make feature layer from my input data
arcpy.MakeFeatureLayer_management(inSAO, "LayerAll", querySAOall)

# Select by attribute and switch the selection
arcpy.SelectLayerByAttribute_management ("LayerAll", "SWITCH_SELECTION")

For me in the second case, the second "arcpy.SelectLayerByAttribute_management" line should return 0 because it is trying to select from a "SWITCH_SELECTION", and in the previous arcpy.MakeFeatureLayer_managemen we only select records with the condition querySAOall

arcpy.MakeFeatureLayer_management(inSAO", "LayerAll", querySAOall) arcpy.SelectLayerByAttribute_management ("LayerAll", "SWITCH_SELECTION")

Please advise.

Re: Arcpy query data and switch selection

DavidPike — Thu, 04 Mar 2021 21:23:13 GMT

I dont think the query in makefeaturesmanagement is making a layer where those features matching the query are selected, rather it is creating a layer which is a subset which matches the query.

The switch selection is therefore taking none selected to all selected.

Re: Arcpy query data and switch selection

JoshuaBixby — Thu, 04 Mar 2021 22:58:22 GMT

David is correct, passing an SQL WHERE clause to MakeFeatureLayer creates a layer with a DefinitionQuery set to the SQL WHERE clause. The definition query is separate from selections and applies before the Select By tools.