DiagrammeR (version 0.9.2)

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.

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 {
# Set a seed
set.seed(23)

# Create a node data frame (ndf)
ndf <-
  create_node_df(
    n = 26,
    label = TRUE,
    type = c(rep("a", 7),
             rep("b", 9),
             rep("c", 8),
             rep("d", 2)))

# Create an edge data frame (edf)
edf <-
  create_edge_df(
    from = sample(1:26, replace = TRUE),
    to = sample(1:26, 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 = ndf,
    edges_df = edf)

# Get counts of nodes grouped by the
# `type` attribute
node_count(graph, type = TRUE)
#> a b c d
#> 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 a specified type
node_count(graph, type = "a")
#> [1] 7

# Get a count of nodes of 2 different types
node_count(graph, type = c("a", "c"))
#> [1] 15
# }

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