

_B_u_i_l_t-_i_n _C_o_n_s_t_a_n_t_s

     LETTERS
     letters
     month.abb
     month.name
     pi

_V_a_l_u_e:

     R has a limited number of built-in constants (there is
     also a rather larger library of data sets which can be
     loaded with the function `data').

     The following constants are available:

 LETTERS: the 26 upper-case letters of the Roman alphabet;

 letters: the 26 lower-case letters of the Roman alphabet;

month.abb: the three-letter abbreviations for the English
          month-names;

month.name: The English names for the months of the year;

      pi: the ratio of the circumference of a circle to its
          diameter.

_S_e_e _A_l_s_o:

     `data'.

_E_x_a_m_p_l_e_s:

       all(nchar(letters) == 1)                    # TRUE
       all(month.abb == substr(month.name, 1, 3))  # TRUE

