

   CCoollllaappssee AAccccoorrddiinngg ttoo GGrroouuppss

        collapse(object, ...)

   AArrgguummeennttss::

     object: an object to be collapsed, usually a data frame.

        ...: some methods for the generic may require addi-
             tional arguments.

   DDeessccrriippttiioonn::

        This function is generic; method functions can be writ-
        ten to handle specific classes of objects. Currently,
        only a `groupedData' method is available.

   VVaalluuee::

        will depend on the method function used; see the appro-
        priate documentation.

   AAuutthhoorr((ss))::

        Jose Pinheiro and Douglas Bates

   SSeeee AAllssoo::

        `collapse.groupedData'

   EExxaammpplleess::

        ## see the method function documentation

