select_edges_by_node_id {DiagrammeR}

Select edges in a graph using node ID values

Description

Select edges in a graph object of class dgr_graph using node ID values. All edges associated with the provided nodes will be included in the selection.

Usage

select_edges_by_node_id(graph, nodes, set_op = "union")

Arguments

graph

A graph object of class dgr_graph.

nodes

A vector of node IDs for the selection of edges present in the graph.

set_op

The set operation to perform upon consecutive selections of graph edges This can either be as a union (the default), as an intersection of selections with intersect, or, as a difference on the previous selection, if it exists.

Value

A graph object of class dgr_graph.

Examples

# Create a graph with 5 nodes
graph <-
  create_graph() %>%
  add_path(n = 5)

# Create a graph selection by selecting edges
# associated with nodes `1` and `2`
graph <-
  graph %>%
  select_edges_by_node_id(
    nodes = 1:2)

# Get the selection of edges
graph %>% get_selection()

# Perform another selection of edges, with nodes
# `1`, `2`, and `4`
graph <-
  graph %>%
  clear_selection() %>%
  select_edges_by_node_id(
    nodes = c(1, 2, 4))

# Get the selection of edges
graph %>% get_selection()

# Get a fraction of the edges selected over all
# the edges in the graph
graph %>%
  {
    l <- get_selection(.) %>%
      length(.)
    e <- count_edges(.)
    l/e
  }