terms.formula              package:base              R Documentation

_A _f_u_n_c_t_i_o_n _t_o _c_o_n_s_t_r_u_c_t _a _t_e_r_m_s _o_b_j_e_c_t _f_r_o_m _a _f_o_r_m_u_l_a.

_D_e_s_c_r_i_p_t_i_o_n:

     This function takes a formula and some optional arguments and
     constructs a terms object. The terms object can then be used to
     construct a `model.matrix'.

_U_s_a_g_e:

     terms.formula(x, specials=NULL, abb=NULL, data=NULL, neg.out=TRUE,
                   keep.order=FALSE, ...)

_A_r_g_u_m_e_n_t_s:

       x: A formula.

specials: What functions in the formula should be marked as special in
          the terms object.

     abb: Unused in R.

    data: A data frame from which the meaning of the special symbol `.'
          can be inferred. It is unused if there is no `.' in the
          formula.

 neg.out: `TRUE' if terms with a minus, `-' should be removed. If FALSE
          these are kept in and indicate a negative order (for
          fractionate?).

keep.order: A logical value indicating whether the terms should keep
          their positions. If FALSE the terms are reordered so that
          main effects come first.

     ...: further arguments passed to or from other methods.

_D_e_t_a_i_l_s:

     Not all of the options work in the same way that they do in S and
     not all are implemented.

_V_a_l_u_e:

     A `terms' object is returned.

_S_e_e _A_l_s_o:

     `terms.object',  `terms.default'

