>> because when I exam the file content, I find something like: > > C D > C E > C F > B D > B C > A C > A B That's how graph.neighborhood is supposed to work; it gives you the first-order neighborhood of the central vertex, so you will find not only edges that are connected to the central vertex but also edges that go between the _neighbors_ of the central vertex.
-- T. According to documentation: "The neighborhood of a given order o of a vertex v includes all vertices which are closer to v than the order. Ie. order 0 is always v itself, order 1 is v plus its immediate neighbors, order 2 is order 1 plus the immediate neighbors of the vertices in order 1, etc.", is order 1 yielding "immediate neighbors" instead? In my case, passing 0 will actually return nothing rather than vertex v itself... _______________________________________________ igraph-help mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/igraph-help
