leaves {graph} | R Documentation

## Find the leaves of a graph

### Description

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.

### Author(s)

Seth Falcon

### Examples

    data(graphExamples)
    graphExamples[[1]]
    leaves(graphExamples[[1]])

    data(apopGraph)
    leaves(apopGraph, "in")
    leaves(apopGraph, "out")

[Package graph version 1.58.2 Index]