nodeWeights {ROntoTools} | R Documentation

## Retrieve the node weights of a graph

### Description

A generic function that returns the node weights of a graph. If `index` is specified, only the weights of the specified nodes are returned. The user can control which node attribute is interpreted as the weight.

### Usage

    nodeWeights(object, index, ..., attr = "weight", default = 1)

    ## S4 method for signature 'graph,character'
    nodeWeights(object, index, attr, default)

    ## S4 method for signature 'graph,numeric'
    nodeWeights(object, index, attr, default)

    ## S4 method for signature 'graph,missing'
    nodeWeights(object, index, attr, default)

### Arguments

`object` | A graph, any object that inherits the `graph` class.
`index` | If supplied, a character or numeric vector of node names or indices.
`...` | Unused.
`attr` | The name of the node attribute to use as a weight. You can view the list of defined node attributes and their default values using nodeDataDefaults.
`default` | The value to use if `object` has no node attribute named by the value of `attr`. The default is the value 1.

### Details

The weights of all nodes identified by the `index` are returned. If `index` is not supplied, the weights of all nodes are returned.

By default, `nodeWeights` looks for an node attribute with name "weight" and, if found, uses these values to construct the node weight vector. You can make use of attributes stored under a different name by providing a value for the `attr` argument. For example, if `object` is a graph instance with an node attribute named "WTS", then the call `nodeWeights(object, attr="WTS")` will attempt to use those values.

If the graph instance does not have an node attribute with name given by the value of the `attr` argument, `default` will be used as the weight for all nodes. Note that if there is an attribute named by `attr`, then its default value will be used for nodes not specifically customized. See nodeData and nodeDataDefaults for more information.

### Value

A named vector with the node weights. The names of the vector are the names of the specified `index`, or all nodes if `index` was not provided.

### Author(s)

Calin Voichita and Sorin Draghici

### See Also

nodes, nodeData

### Examples

    library(graph)
    V <- LETTERS[1:4]
    g <- graphNEL(nodes = V, edgemode = "directed")
    nodeWeights(g)
    nodeWeights(g, "B")
    nodeWeights(g, attr = "WT", default = 3)

[Package ROntoTools version 2.8.0 Index]