trav_reverse_edge {DiagrammeR} | R Documentation

## Traverse to any reverse edges

### Description

From an active selection of edges in a graph object of class `dgr_graph`, traverse to any available reverse edges between the nodes common to the selected edges. For instance, if an active selection has the edge `1->2` but there is also an (unselected) edge `2->1`, then this function can either switch to the selection of `2->1`, or, incorporate both those edges into the active selection of edges.

### Usage

    trav_reverse_edge(graph, add_to_selection = FALSE)

### Arguments

`graph` | a graph object of class `dgr_graph`.
`add_to_selection` | an option to either add the reverse edges to the active selection of edges (`TRUE`) or switch the active selection entirely to those reverse edges (`FALSE`, the default case).

### Value

a graph object of class `dgr_graph`.

### Examples

    # Create a node data frame (ndf)
    ndf <-
      create_node_df(
        n = 4,
        type = "basic",
        label = TRUE)

    # Create an edge data frame (edf)
    edf <-
      create_edge_df(
        from = c(1, 4, 2, 3, 3),
        to =   c(4, 1, 3, 2, 1))

    # Create a graph with the
    # ndf and edf
    graph <-
      create_graph(
        nodes_df = ndf,
        edges_df = edf)

    # Explicitly select the edges
    # `1`->`4` and `2`->`3`
    graph <-
      graph %>%
      select_edges(
        from = 1,
          to = 4) %>%
      select_edges(
        from = 2,
          to = 3)

    # Get the inital edge selection
    get_selection(graph)
    #> [1] 1 3

    # Traverse to the reverse edges
    # (edges `2`: `4`->`1` and
    # `4`:`3`->`2`)
    graph <-
      graph %>%
      trav_reverse_edge()

    # Get the current selection of edges
    get_selection(graph)
    #> [1] 2 4

[Package DiagrammeR version 0.9.2 Index]