DiagrammeR (version 0.8.2)

node_count: Get count of all nodes or certain types of nodes

Description

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

Usage

node_count(graph, type = FALSE)

Arguments

graph

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

type

either a logical value, where TRUE provides a named vector of node count by type and FALSE (the default) provides a total count, or, a character vector of type values to filter the node count.

Value

a numeric vector of single length.

Examples

## Not run: 
# # Before getting counts of nodes, 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),
#                rel = "letter_to_letter")
# 
# graph <-
#   create_graph(nodes_df = nodes,
#                edges_df = edges,
#                graph_attrs = "layout = neato",
#                node_attrs = c("fontname = Helvetica",
#                               "shape = circle"))
# 
# # Get counts of nodes grouped by the "type" attribute
# node_count(graph, type = TRUE) # the default
# #> a_to_g  h_to_p  q_to_x y_and_z
# #>      7       9       8       2
# 
# # Get a total count of nodes with no grouping
# node_count(graph, type = FALSE)
# #> [1] 26
# 
# # Get a count of nodes of one or more specified types
# node_count(graph, type = "a_to_g")
# #> [1] 7
# 
# node_count(graph, type = c("a_to_g", "q_to_x"))
# #> [1] 15
# ## End(Not run)