R: Extract lme Object Groups

getGroups.lme {nlme}

R Documentation

Extract lme Object Groups

Description

The grouping factors corresponding to the linear mixed-effects model represented by object are extracted. If more than one level is indicated in level, the corresponding grouping factors are combined into a data frame; else the selected grouping factor is returned as a vector.

Usage

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

Arguments

`object`	an object inheriting from class `lme`, representing a fitted linear mixed-effects model.
`form`	this argument is included to make the method function compatible with the generic and is ignored in this method.
`level`	an optional integer vector giving the level(s) of grouping to be extracted from `object`. Defaults to the highest or innermost level of grouping.
`data`	unused
`sep`	character, the separator to use between group levels when multiple levels are collapsed. The default is `'/'`.

Value

either a data frame with columns given by the grouping factors indicated in level, or, when a single level is requested, a factor representing the selected grouping factor.

Author(s)

José Pinheiro and Douglas Bates bates@stat.wisc.edu

Examples

fm1 <- lme(pixel ~ day + day^2, Pixel,
  random = list(Dog = ~day, Side = ~1))
getGroups(fm1, level = 1:2)

[Package nlme version 3.1-166 Index]