Are two vertices adjacent?
The order of the vertices only matters in directed graphs,
where the existence of a directed (v1, v2) edge is queried.
are_adjacent(graph, v1, v2)
graph |
The graph. |
v1 |
The first vertex, tail in directed graphs. |
v2 |
The second vertex, head in directed graphs. |
A logical scalar, TRUE is a (v1, v2) exists in the
graph.
Other structural queries:
[.igraph(),
[[.igraph(),
adjacent_vertices(),
ends(),
get.edge.ids(),
gorder(),
gsize(),
head_of(),
incident_edges(),
incident(),
is_directed(),
neighbors(),
tail_of()
ug <- make_ring(10) ug are_adjacent(ug, 1, 2) are_adjacent(ug, 2, 1) dg <- make_ring(10, directed = TRUE) dg are_adjacent(ug, 1, 2) are_adjacent(ug, 2, 1)
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