neighborhood | R Documentation |
The function returns the neighborhood set of given vertices in the form of list. Optionally user can choose to include the given vertices in the list, too.
neighborhood(graph, index, return.self = FALSE)
graph |
An object of |
index |
Names of nodes, whose neighborhood set should be returned |
return.self |
logical, should the vertex itself also be returned? |
Let v be a vertex in a (di)graph, the out-neighborhood or successor set (N+(v), x belongs to V(G) and v->x) and the in-neighborhood or predecessor set (N-(v), x belongs to V(G) and x->v) are jointly returned.
The returned list is indexed by the given node indices, NULL
is
returned in case of non-existing node.
The nodes are unique, that is, duplicated nodes are removed in results.
A list indexed by the given node indices, each entry containing the neighborhood set of that node (or furthermore including that node).
Jitao David Zhang <jitao_david.zhang@roche.com>
D.B. West. Introduction to Graph Theory, Second Edition. Prentice Hall, 2001
V <- c("Hamburg","Stuttgart","Berlin","Paris","Bremen") E <- list("Hamburg"=c("Berlin","Bremen"), "Stuttgart"=c("Berlin","Paris"), "Berlin"=c("Stuttgart","Bremen"), "Paris"=c("Stuttgart"), "Bremen"=c("Hamburg","Berlin")) g <- new("graphNEL", nodes=V, edgeL=E, edgemode="directed") if(require(Rgraphviz) & interactive()) { plot(g, "neato") } ## simple uses neighborhood(g, "Hamburg") neighborhood(g, c("Hamburg", "Berlin","Paris")) ## in case of non-existing nodes neighborhood(g, c("Stuttgart","Ulm")) ## also applicable to non-directed graphs neighborhood(ugraph(g), c("Stuttgart","Berlin"))
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