

_C_o_n_s_t_r_u_c_t _a_n _x_y_V_e_c_t_o_r _o_b_j_e_c_t

     xyVector(x, y)

_A_r_g_u_m_e_n_t_s:

       x: a numeric vector

       y: a numeric vector of the same length as `x'

_D_e_s_c_r_i_p_t_i_o_n:

     Create an object to represent a set of x-y pairs.  The
     resulting object can be treated as a matrix or as a
     data frame or as a vector.  When treated as a vector it
     reduces to the `y' component only.

     The result of functions such as `predict.spline' is
     returned as an `xyVector' object so the x-values used
     to generate the y-positions are retained, say for pur-
     poses of generating plots.

_V_a_l_u_e:

     An object of class `xyVector' with components

       x: a numeric vector

       y: a numeric vector of the same length as `x'

_A_u_t_h_o_r(_s):

     Douglas Bates and Bill Venables

_E_x_a_m_p_l_e_s:

     data( women )
     ispl <- interpSpline( weight ~ height, women )
     weights <- predict( ispl, seq( 55, 75, len = 51 ))
     class( weights )
     plot( weights )
     weights

