Hi alexandre, Thank you for the reply. I understood the get_2d_array(), but I am trying to understand how to use the set_2d_array() in my code. For example if do: G = Graph() G.add_vertex(10) vprop = G.new_vertex_property("vector<double>") vprop[G.vertex(1)] = [1,1,0,1] The vprop.get_2d_array(pos=[0,1,2,3]) gives me an array of shape (4, G.num_vertices()) where the elements placed in the second column are [1,1,0,1] and the other elements are zeros. In my code I will need to assing to specified vertices an array and I can't understand how to use the pos attribute in the set_2d_array(), because, for example, if I use set_2d_array(np.array([0.5, 0.2, 0.1, 1]), pos=[0,1,2,3]), it assigns to each row of the property map an element of the given array. Is there a way to select the rows and the columns of the property map? -- Sent from: http://main-discussion-list-for-the-graph-tool-project.982480.n3.nabble.com/