drop                  package:base                  R Documentation

_D_r_o_p _R_e_d_u_n_d_a_n_t _E_x_t_e_n_t _I_n_f_o_r_m_a_t_i_o_n

_D_e_s_c_r_i_p_t_i_o_n:

     Delete the dimensions of an array which have only one level.

_U_s_a_g_e:

     drop(x)

_A_r_g_u_m_e_n_t_s:

       x: an array (including a matrix).

_V_a_l_u_e:

     If 'x' is an object with a 'dim' attribute (e.g., a matrix or
     'array'), then 'drop' returns an object like 'x', but with any
     extents of length one removed.  Any accompanying 'dimnames'
     attribute is adjusted and returned with 'x'.

     Array subsetting ('[') performs this reduction unless used with
     'drop = FALSE', but sometimes it is useful to invoke 'drop'
     directly.

_S_e_e _A_l_s_o:

     'drop1' which is used for dropping terms in models.

_E_x_a_m_p_l_e_s:

     dim(drop(array(1:12, dim=c(1,3,1,1,2,1,2))))# = 3 2 2
     drop(1:3 %*% 2:4)# scalar product

