transform                package:base                R Documentation

_T_r_a_n_s_f_o_r_m _a_n _O_b_j_e_c_t, _e._g. _a _D_a_t_a _F_r_a_m_e

_D_e_s_c_r_i_p_t_i_o_n:

     `transform' is a generic function, which-at least currently-only
     does anything useful with dataframes. `transform.default' converts
     its first argument to a dataframe if possible and calls
     `transform.data.frame'.

_U_s_a_g_e:

     transform(x, ...)
     transform.default(x, ...)
     transform.data.frame(x, ...)

_A_r_g_u_m_e_n_t_s:

       x: The object to be transformed

     ...: Further arguments of the form `tag=value'

_D_e_t_a_i_l_s:

     The `...' arguments to `transform.data.frame' are tagged vector
     expressions, which are evaluated in the dataframe `x'.  The tags
     are matched against `names(x)', and for those that match, the
     value replace the corresponding variable in `x', and the others
     are appended to `x'.

_V_a_l_u_e:

     The modified value of `x'.

_N_o_t_e:

     If some of the values are not vectors of the appropriate length,
     you deserve whatever you get!

_A_u_t_h_o_r(_s):

     Peter Dalgaard

_S_e_e _A_l_s_o:

     `subset', `list', `data.frame'

_E_x_a_m_p_l_e_s:

     data(airquality)
     transform(airquality, Ozone = -Ozone)
     transform(airquality, new = -Ozone, Temp = (Temp-32)/1.8)

     attach(airquality)
     transform(Ozone, logOzone = log(Ozone)) # marginally interesting ...
     detach(airquality)

