DiagrammeR (version 0.8.4)

trav_out_node: Traverse from one or more selected edges toward adjacent outward nodes

Description

From a graph object of class dgr_graph move to adjacent nodes from a selection of one or more selected edges where the edges are outward edges to those nodes. This creates a selection of nodes. An optional filter by node attribute can limit the set of nodes traversed to.

Usage

trav_out_node(graph, node_attr = NULL, match = NULL)

Arguments

graph

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

node_attr

an optional character vector of node attribute values for filtering the node ID values returned.

match

an option to provide a logical expression with a comparison operator (>, <, ==, or !=) followed by a number for numerical filtering, or, a character string for filtering the edges returned through string matching.

Value

a graph object of class dgr_graph.

Examples

library(magrittr)

# Create a simple graph
graph <-
 create_graph() %>%
 add_n_nodes(2) %>%
 add_edge(1, 2)

# Traverse from node `1` to the outward edge and
# immediately back to `1` by:
# (1) moving from node `1` to edge `1` -> `2`
# (2) moving from edge `1` -> `2` to node `1`
graph <-
  graph %>%
  select_nodes_by_id(1) %>%
  trav_out_edge %>%
  trav_out_node

# Verify that the selection of node `1` has been
# made by using the `get_selection()` function
get_selection(graph)
#> [1] "1"