getGroups.varFunc {nlme} | R Documentation |
This method function extracts the grouping factor associated with the
variance function represented by object
, if any is present.
getGroups(object)
object |
an object inheriting from class varFunc ,
representing a variance function structure. |
if object
has a groups
attribute, its value is
returned; else NULL
is returned.
Jose Pinheiro and Douglas Bates
library(nlme) data(Orthodont) vf1 <- varPower(form = ~ age | Sex) vf1 <- initialize(vf1, Orthodont) getGroups(vf1)