are_adjacent: Are two vertices adjacent?

In igraph: Network Analysis and Visualization

Are two vertices adjacent?

Description

The order of the vertices only matters in directed graphs, where the existence of a directed ⁠(v1, v2)⁠ edge is queried.

Usage

are_adjacent(graph, v1, v2)

Arguments

graph	The graph.
v1	The first vertex, tail in directed graphs.
v2	The second vertex, head in directed graphs.

Value

A logical scalar, TRUE if edge ⁠(v1, v2)⁠ exists in the graph.

Related documentation in the C library

igraph_are_adjacent().

See Also

Other structural queries: [.igraph(), [[.igraph(), adjacent_vertices(), ends(), get_edge_ids(), gorder(), gsize(), head_of(), incident(), incident_edges(), is_directed(), neighbors(), tail_of()

Examples

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)

igraph documentation built on Oct. 20, 2024, 1:06 a.m.