DiagrammeR (version 0.8.4)

node_present: Determine whether a specified node is present in an existing graph object

Description

From a graph object of class dgr_graph, determine whether a specified node is present.

Usage

node_present(graph, node)

Arguments

graph

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

node

a value that may or may not match a node ID in the graph.

Value

a logical value.

Examples

# Create a node data frame
nodes <-
  create_nodes(
    nodes = LETTERS,
    label = TRUE,
    type = "letter")

# Create an edge data frame
edges <-
  create_edges(
    from = sample(LETTERS, replace = TRUE),
    to = sample(LETTERS, replace = TRUE),
    rel = "letter_to_letter")

# Create a graph
graph <-
  create_graph(nodes_df = nodes,
               edges_df = edges)

# Verify that node with ID `a` is not in graph
node_present(graph, "a")
#> FALSE

# Is node with ID `A` in the graph?
node_present(graph, "A")
#> TRUE

# Are all node ID values from the LETTERS vector
# in the graph?
all(sapply(LETTERS,
      function(x) node_present(graph, x)))
#> TRUE