ArcPy Select (Highlight) All Features In a Specific Group Layer in Current Map [closed]

Question

I am using ArcGIS 10.4.1.

Can you let me know how I can Select/Highlight (I am not going to run any attribute query against the layer and this is just for visualization) all features listed under one specific Group layer?

For example I have a group layer called Streets_line and many features listed under it.

Can you let me know how I can highlight all of them in Current Map?

I already tried this

import arcpy    

mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListLayers(mxd, "Streets_line")[0]
for dfs in arcpy.mapping.ListDataFrames(mxd):
    for lyr in arcpy.mapping.ListLayers(mxd, "Streets_line", dfs):
        arcpy.SelectLayerByAttribute_management (lyr, "NEW_SELECTION", "")

and

mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListLayers(mxd, "Streets_line")[0]
for dfs in arcpy.mapping.ListDataFrames(mxd):
    for lyr in arcpy.mapping.ListLayers(mxd, "Streets_line", dfs):
        arcpy.SelectLayerByAttribute_management (lyr.name, "NEW_SELECTION", "")

but I am getting this error

Runtime error  Traceback (most recent call last):   File "<string>", line 6, in <module>   
File "c:\program files (x86)\arcgis\desktop10.4\arcpy\arcpy\management.py", line 7182, in SelectLayerByAttribute     
raise e ExecuteError: 
ERROR 000840: The value is not a Table View. 
ERROR 000840: The value is not a Raster Layer. 
ERROR 000840: The value is not a Mosaic Layer.

Answer 1

You are getting that error because it is trying to select features in your group layer (which is impossible). You need your loop to test that the layer you are selecting is not a group layer (using if not lyr.isGroupLayer) or even better, test that it is a feature layer (using if lyr.isFeatureLayer)

mxd = arcpy.mapping.MapDocument("CURRENT")
sl = arcpy.mapping.ListLayers(mxd, "Streets_line")[0]
for lyr in arcpy.mapping.ListLayers(sl):
    if lyr.isFeatureLayer: # Only run the selection if a feature layer
        arcpy.SelectLayerByAttribute_management(lyr, "NEW_SELECTION")