Character string, either “in”, “out” or
“all”. If “in” all vertices from which v is reachable
are listed. If “out” all vertices reachable from v are
returned. If “all” returns the union of these. It is ignored for
undirected graphs.

Value

Numeric vector, the ids of the vertices in the same component as
v.

Details

A breadh-first search is conducted starting from vertex v.