DiagrammeR (version 1.0.0)

set_edge_attr_to_display: Set the edge attribute values to be rendered

Description

Set a edge attribute type to display as edge text when calling the render_graph() function. This allows for display of different types of edge attribute values on a per-edge basis. Without setting the display attribute, rendering a graph will default to not printing any text on edges. Setting the display edge attribute with this function for the first time (i.e., the display column doesn't exist in the graph's internal edge data frame) will insert the attr value for all edges specified in edges and a default value (default) for all remaining edges.

Usage

set_edge_attr_to_display(graph, attr = NULL, edges = NULL,
  default = "label")

Arguments

graph

a graph object of class dgr_graph.

attr

the name of the attribute from which label text for the edge will be obtained. If set to NULL, then NA values will be assigned to the display column for the chosen edges.

edges

a length vector containing one or several edge ID values (as integers) for which edge attributes are set for display in the rendered graph. If NULL, all edges from the graph are assigned the display value given as attr.

default

the name of an attribute to set for all other graph edges not included in edges. This value only gets used if the display edge attribute is not in the graph's internal edge data frame.

Value

a graph object of class dgr_graph.

Examples

# NOT RUN {
# Create a random graph using the
# `add_gnm_graph()` function
graph <-
  create_graph() %>%
  add_gnm_graph(
    n = 4,
    m = 4,
    set_seed = 23) %>%
  set_edge_attrs(
    edge_attr = value,
    values = c(2.5, 8.2, 4.2, 2.4))

# For edge ID values of `1`,
# `2`, and `3`, choose to display
# the edge `value` attribute (for
# the other edges, display nothing)
graph <-
  graph %>%
  set_edge_attr_to_display(
    edges = 1:3,
    attr = value,
    default = NA)

# Show the graph's edge data frame; the
# `display` edge attribute will show, for
# each row, which edge attribute value to
# display when the graph is rendered
graph %>%
  get_edge_df()

# This function can be called multiple
# times on a graph; after the first time
# (i.e., creation of the `display`
# attribute), the `default` value won't
# be used
graph %>%
  set_edge_attr_to_display(
    edges = 4,
    attr = to) %>%
  set_edge_attr_to_display(
    edges = c(1, 3),
    attr = id) %>%
  get_edge_df()
# }