latticeParseFormula         package:lattice         R Documentation

_P_a_r_s_e _T_r_e_l_l_i_s _f_o_r_m_u_l_a

_D_e_s_c_r_i_p_t_i_o_n:

     this function is used by high level Lattice functions like
     'xyplot' to parse the formula argument and evaluate various
     components of the data.

_U_s_a_g_e:

     latticeParseFormula(model, data, dimension = 2,
                         subset = TRUE, groups = NULL,
                         multiple, outer,
                         subscripts,
                         drop)

_A_r_g_u_m_e_n_t_s:

   model: the model/formula to be parsed.  This can be in either of two
          possible forms, one for 2d and one for 3d formulas,
          determined by the 'dimension' argument. The 2d formulas are
          of the form 'y ~ x| g1 * ... *gn', and the 3d formulas are of
          the form 'z ~ x * y | g1 * ...* gn'. In the first form, 'y'
          may be omitted. The conditioning variables 'g1, ...,gn' can
          be omitted in either case. 

    data: the environment/dataset where the variables in the  formula
          are evaluated. 

dimension: dimension of the model, see above

  subset: index for choosing a subset of the data frame 

  groups: the grouping variable, if present

multiple, outer: logicals, determining how a '+' in the y and x
          components of the formula are processed. See 'xyplot' for
          details 

subscripts: logical, whether subscripts are to be calculated 

    drop: logical or list, similar to the 'drop.unused.levels' argument
          in 'xyplot', indicating whether unused levels of conditioning
          factors and data variables that are factors are to be
          dropped. 

_V_a_l_u_e:

     returns a list with several components, including 'left, right,
     left.name, right.name, condition' for 2-D, and 'left, right.x,
     right.y, left.name, right.x.name, right.y.name, condition' for
     3-D. Other possible components are groups, subscr

_A_u_t_h_o_r(_s):

     Saikat DebRoy, Deepayan Sarkar Deepayan.Sarkar@R-project.org

_S_e_e _A_l_s_o:

     'xyplot', 'Lattice'