Use this if you are using igraph from R
If attributes are supplied, and they are not present in the graph,
their values for the original vertices of the graph are set to
NA.
add_vertices(graph, nv, ..., attr = list())
| graph | The input graph. | 
| nv | The number of vertices to add. | 
| ... | Additional arguments, they must be named, and they will be added as vertex attributes, for the newly added vertices. See also details below. | 
| attr | A named list, its elements will be added as vertex attributes, for the newly added vertices. See also details below. | 
The graph, with the vertices (and attributes) added.
Other functions for manipulating graph structure: 
+.igraph(),
add_edges(),
delete_edges(),
delete_vertices(),
edge(),
igraph-minus,
path(),
vertex()
g <- make_empty_graph() %>% add_vertices(3, color = "red") %>% add_vertices(2, color = "green") %>% add_edges(c(1,2, 2,3, 3,4, 4,5)) g V(g)[[]] plot(g)