Extract corStruct Groups
Usage
getGroups(object, form, data, level)
Arguments
object
|
an object inheriting from class corStruct
representing a correlation structure.
|
form
|
this argument is included to make the method function
compatible with the generic. It will be assigned the value of
formula(object) and should not be modified.
|
data
|
an optional data frame in which to evaluate the variables
defined in form , in case object is not initialized and
the grouping factor needs to be evaluated.
|
level
|
this argument is included to make the method function
compatible with the generic and is not used.
|
Description
This method function extracts the grouping factor associated with
object
, if any is present.Value
if a grouping factor is present in the correlation structure
represented by object
, the function returns the corresponding
factor vector; else the function returns NULL
.Author(s)
Jose Pinheiro and Douglas BatesSee Also
getGroups
Examples
library(lme)
data(Orthodont)
cs1 <- corAR1(form = ~ 1 | Subject)
getGroups(cs1, data = Orthodont)