Manipulating the graph object

Once you have a network object, you will want to explore it and access parts of it or extract info from it.

Here is a table with some of the functions you’ll use all the time in any SNA project.

Print the graph object
Manipulate the graph object
snafun	`snafun::print(x)`
igraph¹	`igraph::print.igraph(x)`
network¹	`network::print.network(x)`
Check characteristics of the graph object
snafun	`snafun::has_edge_attributes(x) snafun::has_vertex_attributes(x) snafun::has_vertex_attribute(x, attrname) snafun::has_edge_attribute(x, attrname) snafun::has_vertexnames(x) snafun::has_loops(x) snafun::is_bipartite(x) snafun::is_connected(x, rule = c("weak", "strong")) snafun::is_directed(x) snafun::is_network(x) snafun::is_igraph(x) snafun::is_signed(x) snafun::is_weighted(x)`
igraph	`# various functions, including igraph::any_loop(g) igraph::any_multiple(g) igraph::is_bipartite(graph) igraph::is_connected(graph, mode = c("weak", "strong")) igraph::is_directed(graph) igraph::is_igraph(graph) igraph::is_named(graph) igraph::is_simple(graph) igraph::is_weighted(graph)`
network	`# various functions, including: network::has.loops(x) network::is.bipartite(x) network::is.directed(x) network::is.multiplex(x) network::is.network(x) sna::is.connected(g, connected = "strong")`
Access the vertices and edges
snafun	—
igraph	`igraph::V(x) # vertices igraph::E(x) # edges`
network	—
Extract vertex / edge / graph attributes
snafun	`snafun::extract_vertex_attribute(x, name) snafun::extract_vertex_names(x) # specific to access the vertex names attribute snafun::extract_edge_attribute(x, name) snafun::extract_graph_attribute(x, name)`
igraph	`igraph::vertex_attr(graph, name, index = V(graph)) igraph::V(graph) $attributename igraph::edge_attr(graph, name, index = E(graph)) igraph::E(graph)$ attributename igraph::graph_attr(graph, name)`
network²	`network::get.vertex.attribute(x, attrname) network::get.edge.attribute(x, attrname) network::get.network.attribute(x, attrname)`
igraph	—
network	—
Extract the ID of an edge
snafun	`snafun::extract_edge_id(object, ego, alter, edgelist)`
Extract vertex names
snafun	`snafun::extract_vertex_names(x)`
igraph	`igraph::V(x)$name igraph::vertex_attr(x, name = "names")`
network	`network::get.vertex.attribute(x, "vertex.names") network::network.vertex.names(x)`
set vertex names
snafun	`snafun::add_vertex_names(x, value)`
igraph	`igraph::V(x)$name <- value igraph::set_vertex_attr(x, name = "names")`
network	`network::set.vertex.attr(x, "vertex.names", value) network::network.vertex.names(x) <- value`
List vertex / edge / graph attributes
snafun	`snafun::list_vertex_attribute(x, name) snafun::list_edge_attribute(x, name) snafun::list_graph_attribute(x, name)`
igraph	`igraph::vertex_attr_names(graph) igraph::edge_attr_names(graph) igraph::graph_attr_names(graph)`
network	`network::list.vertex.attributes(x) network::list.edge.attributes(x network::list.network.attributes(x)`
Extract all vertex attributes into a data.frame
snafun	`snafun::extract_all_vertex_attributes(g)`
igraph	—
network	—
Add vertex / edge / graph attributes
snafun	`# very flexible and powerful functions to add attributes # in several ways, with the same function snafun::add_edge_attributes(object, attr_name, value, edgelist, overwrite = FALSE) snafun::add_vertex_attributes(x, attr_name = NULL, value) snafun::add_graph_attribute(x, attr_name = NULL, value)`
igraph	`igraph::set_edge_attr(g, "name", value) igraph::E(g) $name <- value igraph::set_vertex_attr(g, "name", value) igraph::V(g)$ name <- value igraph::set_graph_attr(g, "name", value) g$name <- value`
network	`network::set.edge.attribute(g, "new_name", value, e = seq_along(g $mel)) network::set.edge.value(g, "new_name", value, e = seq_along(g$ mel)) network::set.network.attribute(g, "new_name", value) network::set.vertex.attribute(g, "new_name", value, v = seq_len(network::network.size(g)))`
Remove vertex / edge / graph attributes
snafun	`snafun::remove_edge_attribute(x, attr_name) snafun::remove_edge_weight(x) # remove edge weights snafun::remove_vertex_attribute(x, attr_name) snafun::remove_vertex_names(x) # specific for the vertex name attribute snafun::remove_graph_attribute(x, attr_name)`
igraph	`igraph::delete_edge_attr(graph, name) igraph::delete_vertex_attr(graph, name) igraph::delete_graph_attr(graph, name)`
network	`network::delete.edge.attribute(x, attrname, ...) network::delete.vertex.attribute(x, attrname, ...) network::delete.network.attribute(x, attrname, ...)`
Add vertices or edges
snafun	—
igraph	`igraph::add_vertices(graph, nv, ..., attr = list()) igraph::add_edges(graph, edges, ..., attr = list())`
network	`network::add.vertices(x, nv, vattr = NULL, last.mode = TRUE, ...) network::add.edge(x, tail, head, names.eval = NULL, vals.eval = NULL, edge.check = FALSE, ...) network::add.edges(x, tail, head, names.eval = NULL, vals.eval = NULL, ...)`
Remove vertices or edges
snafun	`snafun::remove_vertices(x, vertices)`
igraph	`igraph::delete_vertices(graph, v) igraph::delete_edges(graph, edges)`
network	`network::delete.edges(x, eid) network::delete.vertices(x, vid)`
Contract vertices into one
snafun	`snafun::contract_vertices(g, vertices, method = c("min", "max", "union", "add"), attr = NULL, new_name = "set", out_as_igraph = TRUE)`
igraph	—
network	—
Extract a subset from the graph
snafun	`# single function to do it all snafun::extract_subgraph(x, v_to_keep, e_to_keep)`
igraph	`# subset based on vertices igraph::induced_subgraph(g, vids = theVerticesYouWantToKeep) # subset based on edges igraph::subgraph.edges(g, eids = theEdgesYouWantToKeep)`
network	`# subset based on vertices network::get.inducedSubgraph(g, v = theVerticesYouWantToKeep) # subset based on edges network::get.inducedSubgraph(g, eid = theEdgesYouWantToKeep)`
Extract egonets from the graph
snafun	`snafun::extract_egonet(x, vertices = NULL, order = 1, type = c("all", "out", "in"))`
igraph	`igraph::make_ego_graph(g, order = 1, nodes = V(graph), mode = c("all", "out", "in"), mindist = 0)`
network	`sna::ego.extract(dat, ego = NULL, neighborhood = c("combined", "in", "out"))`
Clean up the graph
snafun	`snafun::find_isolates(x, names = TRUE, loops = FALSE) snafun::remove_isolates(x, loops = FALSE) snafun::remove_loops(x)`
igraph	`igraph::simplify(g) # for example igraph::simplify(g, remove.multiple = TRUE, remove.loops = TRUE, edge.attrib.comb = list(weight = 'max'))`
network	`sna::isolates(g, diag=FALSE)`
Union of graphs
snafun	`snafun::make_union(net1, net2, net3, byname = 'auto')`
igraph	`igraph::union(net1, net2, net3)`
network	—
Intersection of graphs
snafun	`snafun::extract_intersection(net, net2, net3, byname = 'auto', keep.all.vertices = TRUE)`
igraph	`igraph::intersection(net, net2, net3)`
network	—
¹ Often, but certainly not always, it will also work if you just use `print(x)`
² These functions have many additional arguments