Add Edges to an Adjacency List

`add_edge(adj, v1, v2, ids = NULL, zero = TRUE)`

- adj
list of adjacent precincts

- v1
vector of vertex identifiers for the first vertex. Can be an integer index or a value to look up in

`ids`

, if that argument is provided. If more than one identifier is present, connects each to corresponding entry in v2.- v2
vector of vertex identifiers for the second vertex. Can be an integer index or a value to look up in

`ids`

, if that argument is provided. If more than one identifier is present, connects each to corresponding entry in v2.- ids
A vector of identifiers which is used to look up the row indices for the vertices. If provided, the entries in

`v1`

and`v2`

must match exactly one entry in`ids`

.- zero
boolean, TRUE if the list is zero indexed. False if one indexed.

adjacency list.

```
data(towns)
adj <- adjacency(towns)
add_edge(adj, 2, 3)
#> [[1]]
#> [1] 3 4 6
#>
#> [[2]]
#> [1] 4 2
#>
#> [[3]]
#> [1] 3 5 1
#>
#> [[4]]
#> [1] 0 4 2 6 5
#>
#> [[5]]
#> [1] 0 1 3 5
#>
#> [[6]]
#> [1] 3 4 2 6
#>
#> [[7]]
#> [1] 0 3 5
#>
add_edge(adj, "West Haverstraw", "Stony Point", towns$MUNI)
#> [[1]]
#> [1] 3 4 6
#>
#> [[2]]
#> [1] 4
#>
#> [[3]]
#> [1] 3 5
#>
#> [[4]]
#> [1] 0 4 2 6 5 5
#>
#> [[5]]
#> [1] 0 1 3 5
#>
#> [[6]]
#> [1] 3 4 2 6 3
#>
#> [[7]]
#> [1] 0 3 5
#>
```