Use this if you are using igraph from R
This function creates a new graph, by merging several vertices into one. The vertices in the new graph correspond to sets of vertices in the input graph.
contract(graph, mapping, vertex.attr.comb = igraph_opt("vertex.attr.comb"))
graph |
The input graph, it can be directed or undirected. |
mapping |
A numeric vector that specifies the mapping. Its elements correspond to the vertices, and for each element the id in the new graph is given. |
vertex.attr.comb |
Specifies how to combine the vertex attributes in
the new graph. Please see |
The attributes of the graph are kept. Graph and edge attributes are
unchanged, vertex attributes are combined, according to the
vertex.attr.comb
parameter.
A new graph object.
Gabor Csardi csardi.gabor@gmail.com
g <- make_ring(10) g$name <- "Ring" V(g)$name <- letters[1:vcount(g)] E(g)$weight <- runif(ecount(g)) g2 <- contract(g, rep(1:5, each=2), vertex.attr.comb=toString) ## graph and edge attributes are kept, vertex attributes are ## combined using the 'toString' function. print(g2, g=TRUE, v=TRUE, e=TRUE)