DiagrammeR (version 0.8.2)

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

## Not run: 
# # Before getting node ID values for predecessors of
# # a specified node, 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),
#                label = "edge",
#                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 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
# ## End(Not run)