DiagrammeR (version 0.9.2)

is_edge_loop: Is the edge a loop edge?

Description

Determines whether an edge definition is a loop edge.

Usage

is_edge_loop(graph, edge)

Arguments

graph

a graph object of class dgr_graph.

edge

a numeric edge ID value.

Value

a logical value.

Examples

# NOT RUN {
# Create a graph that has multiple
# loop edges
graph <-
  create_graph() %>%
  add_path(n = 4) %>%
  add_edge(
    from = 1,
    to = 1) %>%
  add_edge(
    from = 3,
    to = 3)

# Get the graph's internal
# edge data frame
graph %>%
  get_edge_df()
#>   id from to  rel
#> 1  1    1  2 <NA>
#> 2  2    2  3 <NA>
#> 3  3    3  4 <NA>
#> 4  4    1  1 <NA>
#> 5  5    3  3 <NA>

# Determine if edge `4` is
# a loop edge
graph %>%
  is_edge_loop(edge = 4)
#> [1] TRUE

# Determine if edge `2` is
# a loop edge
graph %>%
  is_edge_loop(edge = 2)
#> [1] FALSE
# }