

_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, all of the same length.

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

     `order' returns a permutation which rearranges its
     first argument into ascending order, breaking ties by
     further arguments.

_D_e_t_a_i_l_s:

     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 (see 1st example).

     `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:

     (ii <- order(x <- c(1,1,3:1,1:4,3), y <- c(9,9:1), z <-c(2,1:9)))
     ## 6  5  2  1  7  4 10  8  3  9
     rbind(x,y,z)[,ii] # shows the reordering (ties via 2nd & 3rd arg)

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

