DiagrammeR (version 0.9.2)

get_node_ids: Get a vector of node ID values

Description

Obtain a vector of node ID values from a graph object or a node data frame. An optional filter by node attribute can limit the set of node ID values returned.

Usage

get_node_ids(x, conditions = NULL)

Arguments

x

either a graph object of class dgr_graph or a node data frame.

conditions

an option to use filtering conditions for the retrieval of nodes.

Value

a vector of node ID values.

Examples

# NOT RUN {
# Create a node data frame (ndf)
ndf <-
  create_node_df(
    n = 4,
    type = "letter",
    color = c("red", "green",
              "blue", "blue"),
    value = c(3.5, 2.6, 9.4, 2.7))

# Create a graph
graph <- create_graph(nodes_df = ndf)

# Get a vector of all nodes in a graph
get_node_ids(graph)
#> [1] 1 2 3 4

# Get a vector of node ID values from a
# node data frame
get_node_ids(ndf)
#> [1] 1 2 3 4

# Get a vector of node ID values using a
# numeric comparison (i.e., all nodes with
# `value` attribute greater than 3)
get_node_ids(
  graph,
  conditions = value > 3)
#> [1] 1 3

# Get a vector of node ID values using
# a match pattern (i.e., all nodes with
# `color` attribute of `green`)
get_node_ids(
  graph,
  conditions = color == "green")
#> [1] 2

# Use multiple conditions to return nodes
# with the desired attribute values
get_node_ids(
  graph,
  conditions =
    color == "blue" &
    value > 5)
#> [1] 3
# }

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