edge_present {DiagrammeR} | R Documentation |
From a graph object of class
dgr_graph
, determine whether a directed edge
(defined by a pair of node IDs extant in the graph)
is present.
edge_present(graph, from, to)
graph |
a graph object of class
|
from |
a node ID from which the edge to be queried is outgoing. |
to |
a node ID to which the edge to be queried is incoming. |
a logical value.
# Create a node data frame (ndf) nodes <- create_nodes( nodes = LETTERS, label = TRUE, type = c(rep("a_to_g", 7), rep("h_to_p", 9), rep("q_to_x", 8), rep("y_and_z", 2))) # Create an edge data frame (edf) edges <- create_edges( from = sample(LETTERS, replace = TRUE), to = sample(LETTERS, replace = TRUE), rel = "letter_to_letter") # Create a graph using the ndf and edf graph <- create_graph( nodes_df = nodes, edges_df = edges) # Is there any edge between nodes with IDs # `A` and `B`? edge_present(graph, from = "A", to = "B") #> FALSE # Verify that there is an edge between nodes # `K` and `V` edge_present(graph, from = "K", to = "V") #> TRUE