getGroups.lme              package: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):

     Jose Pinheiro Jose.Pinheiro@pharma.novartis.com and Douglas Bates
     bates@stat.wisc.edu

See Also:

     'lme'

Examples:

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

