

_O_r_d_e_r_i_n_g _P_e_r_m_u_t_a_t_i_o_n

     order(...)

_A_r_g_u_m_e_n_t_s:

     ...: a sequence of vectors.

_D_e_s_c_r_i_p_t_i_o_n:

     `order' returns a permutation which will rearrange its
     first argument into ascending order.  In the case of
     ties in the first vector, values in the second are used
     to break the ties.  If the values are still tied,
     values in the later arguments are used to break the
     tie.

     `NA' values are treated as greater than any other
     values so that permutations returned by `order' move
     `NA' values to the top end of the array.

_S_e_e _A_l_s_o:

     `sort' and `rank'.

_E_x_a_m_p_l_e_s:

     x <- c(5:1, 6:8, 12:9)
     y <- (x - 5)^2
     # rearrange matched vectors so that
     # the first is in ascending order
     o <- order(x)
     rbind(x[o], y[o])

