DiagrammeR (version 0.8.4)

get_predecessors: Get node IDs for predecessor nodes to the specified node

Description

Provides a vector of node IDs for all nodes that have a connection to the given node.

Usage

get_predecessors(graph, node)

Arguments

graph

a graph object of class dgr_graph.

node

a node ID for the selected node.

Value

a vector of node ID values.

Examples

# Create a node data frame (ndf)
nodes <-
  create_nodes(
    nodes = LETTERS)

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

# From the ndf and edf, create a graph object
graph <-
  create_graph(
    nodes_df = nodes,
    edges_df = edges)

# Get predecessors for node `Z` in the graph
get_predecessors(graph, node = "Z")
#> [1] "A" "R" "R"

# If there are no predecessors, NA is returned
get_predecessors(graph, node = "A")
#> [1] NA