DiagrammeR (version 0.8.4)

edge_count: Get count of all edges or edges with distinct relationship types

Description

From a graph object of class dgr_graph, get a count of edges in the graph and optionally obtain a count of edges by their relationship type.

Usage

edge_count(graph, rel = FALSE)

Arguments

graph

a graph object of class dgr_graph that is created using create_graph.

rel

either a logical value, where TRUE provides a named vector of edge count by type and FALSE (the default) provides a total count of edges, or, a string corresponding to one or more edge relationship types.

Value

a numeric vector of single length.

Examples

# 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 = c(rep("rel_a", 7),
            rep("rel_b", 9),
            rep("rel_c", 8),
            rep("rel_d", 2)))

# Create a graph using the ndf and edf
graph <-
  create_graph(
    nodes_df = nodes,
    edges_df = edges)

# Get a total count of edges in the graph
edge_count(graph, rel = FALSE)
#> [1] 26

# Get a count of edges that have the relationship
# `rel_a`
edge_count(graph, rel = "rel_a")
#> [1] 7

# Get a count of edges with relationships
# `rel_a` and `rel_b`
edge_count(graph, rel = c("rel_a", "rel_b"))
#> [1] 16