nlme (version 3.1-78)

getGroups.varFunc: Extract varFunc Groups

Description

This method function extracts the grouping factor associated with the variance function represented by object, if any is present.

Usage

## S3 method for class 'varFunc':
getGroups(object, form, level, data, sep)

Value

if object has a groups attribute, its value is returned; else NULL is returned.

Examples

vf1 <- varPower(form = ~ age | Sex)
vf1 <- Initialize(vf1, Orthodont)
getGroups(vf1)