is.empty.model             package:stats             R Documentation

_C_h_e_c_k _i_f _a _M_o_d_e_l _i_s _E_m_p_t_y

_D_e_s_c_r_i_p_t_i_o_n:

     R model notation allows models with no intercept and no
     predictors. These require special handling internally. 
     'is.empty.model()' checks whether an object describes an empty
     model.

_U_s_a_g_e:

     is.empty.model(x)

_A_r_g_u_m_e_n_t_s:

       x: A 'terms' object or an object with a 'terms' method.

_V_a_l_u_e:

     'TRUE' if the model is empty

_S_e_e _A_l_s_o:

     'lm','glm'

_E_x_a_m_p_l_e_s:

     y <- rnorm(20)
     is.empty.model(y ~ 0)
     is.empty.model(y ~ -1)
     is.empty.model(lm(y ~ 0))