coef.lmList               package:nlme               R Documentation

Extract lmList Coefficients

Description:

     The coefficients of each 'lm' object in the 'object' list are
     extracted and organized into a data frame, with rows corresponding
     to the 'lm' components and columns corresponding to the
     coefficients.  Optionally, the returned data frame may be
     augmented with covariates summarized over the groups associated
     with the 'lm' components.

Usage:

     ## S3 method for class 'lmList':
     coef(object, augFrame, data, which, FUN,
        omitGroupingFactor, ...)

Arguments:

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

augFrame: an optional logical value. If 'TRUE', the returned data frame
          is augmented with variables defined in the data frame used to
          produce 'object'; else, if 'FALSE', only the coefficients are
          returned. Defaults to 'FALSE'. 

    data: an optional data frame with the variables to be used for
          augmenting the returned data frame when 'augFrame = TRUE'.
          Defaults to the data frame used to fit 'object'.

   which: an optional positive integer or character vector specifying
          which columns of the data frame used to produce 'object'
          should be used in the augmentation of the returned data
          frame. Defaults to all variables in the data. 

     FUN: an optional summary function or a list of summary functions
          to be applied to group-varying variables, when collapsing the
          data by groups.  Group-invariant variables are always
          summarized by the unique value that they assume within that
          group. If 'FUN' is a single function it will be applied to
          each non-invariant variable by group to produce the summary
          for that variable.  If 'FUN' is a list of functions, the
          names in the list should designate classes of variables in
          the frame such as 'ordered', 'factor', or 'numeric'.  The
          indicated function will be applied to any group-varying
          variables of that class.  The default functions to be used
          are 'mean' for numeric factors, and 'Mode' for both 'factor'
          and 'ordered'.  The 'Mode' function, defined internally in
          'gsummary', returns the modal or most popular value of the
          variable.  It is different from the 'mode' function that
          returns the S-language mode of the variable. 

omitGroupingFactor: an optional logical value.  When 'TRUE' the
          grouping factor itself will be omitted from the group-wise
          summary of 'data' but the levels of the grouping factor will
          continue to be used as the row names for the returned data
          frame. Defaults to 'FALSE'. 

     ...: some methods for this generic require additional arguments. 
          None are used in this method.

Value:

     a data frame inheriting from class 'coef.lmList' with the
     estimated coefficients for each 'lm' component of 'object' and,
     optionally, other covariates summarized over the groups
     corresponding to the 'lm' components. The returned object also
     inherits from classes 'ranef.lmList' and 'data.frame'.

Author(s):

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

References:

     Pinheiro, J. C. and Bates, D. M. (2000), _Mixed-Effects Models in
     S and S-PLUS_, Springer, New York, esp. pp. 457-458.

See Also:

     'lmList', 'fixed.effects.lmList', 'ranef.lmList',
     'plot.ranef.lmList', 'gsummary'

Examples:

     fm1 <- lmList(distance ~ age|Subject, data = Orthodont)
     coef(fm1)
     coef(fm1, augFrame = TRUE)

