This was already added recently (if I understand you correctly), see http://lists.gnu.org/archive/html/igraph-help/2009-11/msg00240.html
That thread also shows a simpler way to keep the vertex attributes.
This was already added recently (if I understand you correctly), see lists.gnu. org/archive/ html/igraph- help/2009- 11/msg00240. html
http://
That thread also shows a simpler way to keep the vertex attributes.