# Add new edges with identical definitions as with a selection of edges

Source:`R/add_forward_edges_ws.R`

`add_forward_edges_ws.Rd`

Add edges in the same direction of one or more edges available as an edge
selection in a graph object of class `dgr_graph`

. New graph edges have the
same edge definitions as those in the selection except with new edge ID
values. There is also the option to assign a common `rel`

grouping to the
newly created edges. Upon addition of the edges, the edge selection will be
retained for further selection or traversal operations.

This function makes use of an active selection of edges (and the function
ending with `_ws`

hints at this).

Selections of edges can be performed using the following selection
(`select_*()`

) functions: `select_edges()`

, `select_last_edges_created()`

,
`select_edges_by_edge_id()`

, or `select_edges_by_node_id()`

.

Selections of edges can also be performed using the following traversal
(`trav_*()`

) functions: `trav_out_edge()`

, `trav_in_edge()`

,
`trav_both_edge()`

, or `trav_reverse_edge()`

.

## Arguments

- graph
A graph object of class

`dgr_graph`

.- rel
An optional string to apply a

`rel`

attribute to all newly created edges.

## See also

Other edge creation and removal:
`add_edge()`

,
`add_edge_clone()`

,
`add_edge_df()`

,
`add_edges_from_table()`

,
`add_edges_w_string()`

,
`add_reverse_edges_ws()`

,
`copy_edge_attrs()`

,
`create_edge_df()`

,
`delete_edge()`

,
`delete_edges_ws()`

,
`delete_loop_edges_ws()`

,
`drop_edge_attrs()`

,
`edge_data()`

,
`join_edge_attrs()`

,
`mutate_edge_attrs()`

,
`mutate_edge_attrs_ws()`

,
`recode_edge_attrs()`

,
`rename_edge_attrs()`

,
`rescale_edge_attrs()`

,
`rev_edge_dir()`

,
`rev_edge_dir_ws()`

,
`set_edge_attr_to_display()`

,
`set_edge_attrs()`

,
`set_edge_attrs_ws()`

## Examples

```
# Create an empty graph, add 2 nodes
# to it, and create the edge `1->2`
graph <-
create_graph() %>%
add_n_nodes(
n = 2,
type = "type_a",
label = c("a_1", "a_2")) %>%
add_edge(
from = 1, to = 2, rel = "a")
# Get the graph's edges
graph %>% get_edge_ids()
#> [1] 1
# Select the edge and create 2
# additional edges with the same
# definition (`1->2`) but with
# different `rel` values (`b` and `c`)
graph <-
graph %>%
select_edges() %>%
add_forward_edges_ws(rel = "b") %>%
add_forward_edges_ws(rel = "c") %>%
clear_selection()
# Get the graph's edge data frame
graph %>% get_edge_df()
#> id from to rel
#> 1 1 1 2 a
#> 2 2 1 2 b
#> 3 3 1 2 c
```