Selection vertex by pymel

really simple question
pm.select (‘obj.vtx[4]’) select vertex but not select object

What’s the question? Are you saying you want it to also select the object?

node = pm.PyNode('obj')

pm.select(node)
pm.select(node.vtx[4], add=True)

# Change the selection mode to component if needed
pm.selectMode(component=True)

thank you very much. ) yes it is exactly what I’m looking for. PyMel documentation says selectMode is not editable so I even don’t try it