Add a multiple of new nodes with edges to or from one or more selected nodes

Add n new nodes to or from one or more nodes available as a selection in a graph object of class dgr_graph. New graph edges will all move either from the nodes in the selection toward the newly created nodes (with the option direction = "from"), or to the selected nodes already in the graph (using direction = "to"). Optionally, set node type and edge rel values for all the new nodes and edges created, respectively.

Selections of nodes can be performed using the following select_... functions: select_nodes(), select_last_nodes_created(), select_nodes_by_degree(), select_nodes_by_id(), or select_nodes_in_neighborhood(). Selections of nodes can also be performed using the following traversal functions: (trav_...): trav_out(), trav_in(), trav_both(), trav_in_node(), trav_out_node().

add_n_nodes_ws(graph, n, direction = NULL, type = NULL, label = NULL,
  rel = NULL, node_aes = NULL, edge_aes = NULL, node_data = NULL,
  edge_data = NULL)

Arguments

graph	a graph object of class dgr_graph.
n	the number of new nodes to attach as successor nodes to the nodes in the selection.
direction	using from will create new edges from existing nodes to the new nodes. The to option will create new edges directed toward the existing nodes.
type	an optional character vector that provides group identifiers for the nodes to be added.
label	an optional character object that describes the nodes to be added.
rel	an optional string to apply a rel attribute to all newly created edges.
node_aes	an optional list of named vectors comprising node aesthetic attributes. The helper function node_aes() is strongly recommended for use here as it contains arguments for each of the accepted node aesthetic attributes (e.g., shape, style, color, fillcolor).
edge_aes	an optional list of named vectors comprising edge aesthetic attributes. The helper function edge_aes() is strongly recommended for use here as it contains arguments for each of the accepted edge aesthetic attributes (e.g., shape, style, penwidth, color).
node_data	an optional list of named vectors comprising node data attributes. The helper function node_data() is strongly recommended for use here as it helps bind data specifically to the created nodes.
edge_data	an optional list of named vectors comprising edge data attributes. The helper function edge_data() is strongly recommended for use here as it helps bind data specifically to the created edges.

Value

a graph object of class dgr_graph.

Examples

# Create an empty graph, add a node to it, select
# that node, and then add 5 more nodes to the graph
# with edges from the original node to all of the
# new nodes
graph <-
  create_graph() %>%
  add_n_nodes(n = 1) %>%
  select_last_nodes_created() %>%
  add_n_nodes_ws(
    n = 5,
    direction = "from")

# Get the graph's nodes
graph %>%
  get_node_ids()
#> [1] 1 2 3 4 5 6
#> [1] 1 2 3 4 5 6

# Get the graph's edges
graph %>%
  get_edges()
#> [1] "1->2" "1->3" "1->4" "1->5" "1->6"
#> "1->2" "1->3" "1->4" "1->5" "1->6"

# Create an empty graph, add a node to it, select
# that node, and then add 5 more nodes to the graph
# with edges toward the original node from all of
# the new nodes
graph <-
  create_graph() %>%
  add_n_nodes(n = 1) %>%
  select_last_nodes_created() %>%
  add_n_nodes_ws(
    n = 5,
    direction = "to")

# Get the graph's nodes
graph %>%
  get_node_ids()
#> [1] 1 2 3 4 5 6
#> [1] 1 2 3 4 5 6

# Get the graph's edges
graph %>%
  get_edges()
#> [1] "2->1" "3->1" "4->1" "5->1" "6->1"
#> "2->1" "3->1" "4->1" "5->1" "6->1"