

   EExxttrraacctt CCoovvaarriiaattee ffrroomm aann OObbjjeecctt

        getCovariate(object, form, data)

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

     object: any object with a `covariate' component

       form: an optional one-sided formula specifying the
             covariate(s) to be extracted. Defaults to `for-
             mula(object)'.

       data: a data frame in which to evaluate the variables
             defined in `form'.

   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. Classes
        which already have methods for this function include
        `corStruct', `corSpatial', `data.frame', and `varFunc'.

   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::

        `getCovariateFormula'

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

        ## see the method function documentation

