Extract varFunc Groups
Usage
getGroups(object)
Arguments
object
|
an object inheriting from class code{varFunc},
representing a variance function structure.
|
Description
This method function extracts the grouping factor associated with the
variance function represented by object
, if any is present.Value
if object
has a groups
attribute, its value is
returned; else NULL
is returned.Author(s)
Jose Pinheiro and Douglas BatesExamples
library(lme)
data(Orthodont)
vf1 <- varPower(form = ~ age | Sex)
vf1 <- initialize(vf1, Orthodont)
getGroups(vf1)