getGroups.lmList {nlme} | R Documentation

## 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 bates@stat.wisc.edu

### See Also

`lmList`

### Examples

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

[Package nlme version 3.1-128 Index]