Obtain a vector, data frame, or list of node IDs associated with edges in a graph object. An optional filter by edge attribute can limit the set of edges returned.

## Arguments

- graph
A graph object of class

`dgr_graph`

.- conditions
an option to use filtering conditions for the retrieval of edges.

- return_type
using

`vector`

(the default), a vector of character objects representing the edges is provided. With`list`

a list object will be provided that contains vectors of outgoing and incoming node IDs associated with edges. With`df`

, a data frame containing outgoing and incoming node IDs associated with edges.- return_values
using

`id`

(the default) results in node ID values returned in the edge definitions. With`label`

, the node labels will instead be used to define edges.

## Examples

```
# Create a node data frame (ndf)
ndf <-
create_node_df(
n = 4,
label = c("one", "two", "three", "four"),
type = "letter",
color = c("red", "green", "grey", "blue"),
value = c(3.5, 2.6, 9.4, 2.7))
# Create an edge data frame (edf)
edf <-
create_edge_df(
from = c(1, 2, 3),
to = c(4, 3, 1),
rel = "leading_to",
color = c("pink", "blue", "blue"),
value = c(3.9, 2.5, 7.3))
# Create a graph
graph <-
create_graph(
nodes_df = ndf,
edges_df = edf)
# Get all edges within a graph, returned as a list
graph %>%
get_edges(
return_type = "vector")
#> [1] "1->4" "2->3" "3->1"
# Get all edges within a graph, returned as a
# data frame
graph %>%
get_edges(
return_type = "df")
#> from to
#> 1 1 4
#> 2 2 3
#> 3 3 1
# Get all edges returned as a list
graph %>%
get_edges(
return_type = "list")
#> [[1]]
#> [1] 1 2 3
#>
#> [[2]]
#> [1] 4 3 1
#>
# Get a vector of edges using
# a numeric comparison (i.e.,
# all edges with a `value`
# attribute greater than 3)
graph %>%
get_edges(
conditions = value > 3,
return_type = "vector")
#> [1] "1->4" "3->1"
# Get a vector of edges using
# a matching condition
graph %>%
get_edges(
conditions = color == "pink",
return_type = "vector")
#> [1] "1->4"
# Use multiple conditions to
# return edges with the
# desired attribute values
graph %>%
get_edges(
conditions =
color == "blue" &
value > 3,
return_type = "vector")
#> [1] "3->1"
# Use `return_values = "label"`
# to return the labels of the
# connected nodes
graph %>%
get_edges(
conditions =
color == "blue" &
value > 3,
return_type = "vector",
return_values = "label")
#> [1] "three->one"
```