getGroups.lmList {nlme}

Extract lmList Object Groups

Description

The grouping factor determining the partitioning of the observations used to produce the lm components of object is extracted.

Usage

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

Arguments

object

an object inheriting from class lmList, representing a list of lm objects with a common model.

form

an optional formula with a conditioning expression on its right hand side (i.e. an expression involving the | operator). Defaults to formula(object). Not used.

level

a positive integer vector with the level(s) of grouping to be used when multiple nested levels of grouping are present. This argument is optional for most methods of this generic function and defaults to all levels of nesting. Not used.

data

a data frame in which to interpret the variables named in form. Optional for most methods. Not used.

sep

character, the separator to use between group levels when multiple levels are collapsed. The default is '/'. Not used.

Value

a vector with the grouping factor corresponding to the lm components of object.

Author(s)

José Pinheiro and Douglas Bates [e-mail]

See Also

lmList

Examples

fm1 <- lmList(distance ~ age | Subject, Orthodont)
getGroups(fm1)