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.
## Not run: # Before finding out whether a particular edge is present, # create a simple graph 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))) edges <- create_edges(from = sample(LETTERS, replace = TRUE), to = sample(LETTERS, replace = TRUE), label = "edge", rel = "letter_to_letter") graph <- create_graph(nodes_df = nodes, edges_df = edges, graph_attrs = "layout = neato", node_attrs = c("fontname = Helvetica", "shape = circle")) # 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 ## End(Not run)