DiagrammeR (version 0.9.2)

add_star: Add a star of nodes to the graph

Description

With a graph object of class dgr_graph, add a node star to the graph.

Usage

add_star(graph, n, type = NULL, label = TRUE, rel = NULL, ...)

Arguments

graph

a graph object of class dgr_graph.

n

the number of nodes comprising the star. The first node will be the center of the star.

type

an optional string that describes the entity type for the nodes to be added.

label

either a vector object of length n that provides optional labels for the new nodes, or, a boolean value where setting to TRUE ascribes node IDs to the label and FALSE yields a blank label.

rel

an optional string for providing a relationship label to all new edges created in the node star.

...

optional node attributes supplied as vectors.

Value

a graph object of class dgr_graph.

Examples

# NOT RUN {
# Create a new graph and add 2 stars of
# varying numbers of nodes
graph <-
  create_graph() %>%
  add_star(
    n = 4,
    type = "four_star") %>%
  add_star(
    n = 5,
    type = "five_star")

# Get node information from this graph
node_info(graph)
#>   id      type label deg indeg outdeg loops
#> 1  1 four_star     1   3     0      3     0
#> 2  2 four_star     2   1     1      0     0
#> 3  3 four_star     3   1     1      0     0
#> 4  4 four_star     4   1     1      0     0
#> 5  5 five_star     1   4     0      4     0
#> 6  6 five_star     2   1     1      0     0
#> 7  7 five_star     3   1     1      0     0
#> 8  8 five_star     4   1     1      0     0
#> 9  9 five_star     5   1     1      0     0

# Attributes can be specified in extra
# arguments and these are applied in order;
# Usually these attributes are applied to
# nodes (e.g., `type` is a node attribute)
# but the `rel` attribute will apply to the
# edges
graph_w_attrs <-
  create_graph() %>%
  add_star(
    n = 6,
    label = c("one", "two",
              "three", "four",
              "five", "six"),
    type = c("a", "a",
             "b", "b",
             "c", "c"),
    value = c(1.2, 8.4,
              3.4, 5.2,
              6.1, 2.6),
    rel = "star")

# Get the graph's node data frame
get_node_df(graph_w_attrs)
#>   id type label value
#> 1  1    a   one   1.2
#> 2  2    a   two   8.4
#> 3  3    b three   3.4
#> 4  4    b  four   5.2
#> 5  5    c  five   6.1
#> 6  6    c   six   2.6

# Get the graph's edge data frame
get_edge_df(graph_w_attrs)
#>   id from to  rel
#> 1  1    1  2 star
#> 2  2    1  3 star
#> 3  3    1  4 star
#> 4  4    1  5 star
#> 5  5    1  6 star
# }