R: Layout nodes using a text-based schematic

layout_nodes_w_string {DiagrammeR}

R Documentation

Layout nodes using a text-based schematic

Description

Layout one or several groups of nodes using a text-based schematic. The option is available to apply sorting to each of the groups.

Usage

layout_nodes_w_string(graph, layout, nodes, sort = NULL, width = 8,
  height = 8, ll = c(0, 0))

Arguments

`graph`	a graph object of class `dgr_graph`.
`layout`	a layout character string that provides a schematic for the layout. This consists of a rectangular collection of `-` characters (for no node placement), and numbers from `1` to `9` (representing different groupings of nodes, further described in the `nodes` argument).
`nodes`	a named vector of the form: `c("1" = "[node_attr]:[value]", ...)`. The LHS corresponds to the numbers used in the `layout` schematic. The RHS provides a shorthand for the node attribute and a value for grouping together nodes (separated by a colon). For instance, with `"type:a"` in the RHS (and `"1"` in the LHS) we would target all nodes with a `type` attribute equal to `a` for positioning in the graph as described by the `1`s in the `layout`.
`sort`	an optional sorting method to apply to the collection of nodes before assigning positional information. Like `nodes`, this is a named vector of the form: `c("1" = "[node_attr]:asc\|desc", ...)`. The `node_attr` in this case should be different than that used in `nodes`. Ideally, this node attribute should have unique values. Choose either `asc` or `desc` right of the colon for ascending or descending sorts.
`width`	the width of the `layout` diagram.
`height`	the height of the `layout` diagram.
`ll`	a vector describing the the lower-left coordinates of the `layout`

Value

a graph object of class dgr_graph.

Examples

# Create a graph with unique labels and
# several node `type` groupings
graph <-
  create_graph() %>%
  add_node(type = "a", label = "a") %>%
  add_node(type = "a", label = "b") %>%
  add_node(type = "b", label = "c") %>%
  add_node(type = "b", label = "d") %>%
  add_node(type = "b", label = "e") %>%
  add_node(type = "c", label = "f") %>%
  add_node(type = "c", label = "g")

# Define a 'layout' for groups of nodes
# using a text string (dashes are empty
# grid cells, numbers--representing
# ad-hoc groupings--correspond to
# individual nodes); here, define a layout
# with 3 groups of nodes
layout <-
"
1--------
1--------
---222---
--------3
--------3
"

# Use the `layout` along with what nodes
# the numbers correspond to in the graph
# with the `nodes` named vectors; the
# optional `sort` vector describes how
# we should sort the collection of node
# before adding position information
graph <-
  graph %>%
  layout_nodes_w_string(
    layout = layout,
    nodes = c("1" = "type:a",
              "2" = "type:b",
              "3" = "type:c"),
    sort = c("1" = "label:asc",
             "2" = "label:desc",
             "3" = "label:desc"))

# Show the graph's node data frame
# to confirm that `x` and `y` values
# were added to each of the nodes
graph %>%
  get_node_df()

[Package DiagrammeR version 1.0.1 Index]