is.R                  package:base                  R Documentation

_A_r_e _w_e _u_s_i_n_g _R, _r_a_t_h_e_r _t_h_a_n _S?

_D_e_s_c_r_i_p_t_i_o_n:

     Test if running under R.

_U_s_a_g_e:

     is.R()

_D_e_t_a_i_l_s:

     The function has been written such as to correctly run in all
     versions of R, S and S-PLUS. In order for code to be runnable in
     both R and S dialects, either your the code must define `is.R' or
     use it as

     `if (exists("is.R") && is.function(is.R) && is.R()) {'
     `    '## R-specific code
     `} else {'
     `    '## S-version of code
     `}'

_V_a_l_u_e:

     `is.R' returns `TRUE' if we are using R and `FALSE' otherwise.

_S_e_e _A_l_s_o:

     `R.version', `system'.

_E_x_a_m_p_l_e_s:

     x <- runif(20); small <- x < 0.4
     # `which()' only exists in R:
     if(is.R()) which(small) else seq(along=small)[small]

