A leaf of an undirected graph is a node with degree equal to one. A
leaf of a directed graph is defined with respect to in-degree or
out-degree. The leaves of a directed graph with respect to in-degree
(out-degree) are those nodes with in-degree (out-degree) equal to
zero.
Usage
leaves(object, degree.dir)
Arguments
object
A graph object
degree.dir
One of "in" or "out". This argument
is ignored when object is undirected and required otherwise.
When degree.dir="in" (degree.dir="out"), nodes have no
in coming (out going) edges will be returned.
Value
A character vector giving the node labels of the leaves.