Unlike many other R functions, these functions modify a graph in place. The shallow copy of the graph is returned invisibly, which can be used with the pipe operator, but does not need to be assigned to a variable.
Usage
add_edges(graph, edges)
add_vertices(graph, n)
delete_edges(graph, eids)
delete_vertices(graph, vids)Arguments
- graph
An
igraph_ptrobject.- edges
An integer vector of vertex IDs; the first two elements are the first edge, etc.
- n
An integer, the number of vertices to add.
- eids
An integer vector of edge IDs.
- vids
An integer vector of vertex IDs.
Value
A shallow copy of the modified igraph_ptr object.
See also
graph_copy() for shallow vs. deep copy of graph objects.
Examples
g = graph_empty()
# The graph is modified in place
add_vertices(g, 6L)
add_edges(g, c(1L, 2L))
g
#> $V tibble [6 × 0] (S3: tbl_df/tbl/data.frame)
#> Named list()
#> # A tibble: 1 × 2
#> from to
#> <int> <int>
#> 1 1 2
# Invisibly returned objects can be used with the pipe operator.
g |>
add_edges(c(3L, 4L)) |>
delete_edges(1L) |>
delete_vertices(6L) |>
print()
#> $V tibble [5 × 0] (S3: tbl_df/tbl/data.frame)
#> Named list()
#> # A tibble: 1 × 2
#> from to
#> <int> <int>
#> 1 3 4
# No need to assign the result
g
#> $V tibble [5 × 0] (S3: tbl_df/tbl/data.frame)
#> Named list()
#> # A tibble: 1 × 2
#> from to
#> <int> <int>
#> 1 3 4