

_L_o_g_i_c_a_l _O_p_e_r_a_t_o_r_s

     ! x
     x & y
     x && y
     x | y
     x || y
     xor(x, y)

_D_e_s_c_r_i_p_t_i_o_n:

     These operators act on logical vectors.

     `!' indicates logical negation (NOT).

     `&' and `&&' indicate logical AND and `|' and `||'
     indicate logical OR.  The shorter form performs ele-
     mentwise comparisons in much the same way as arithmetic
     operators.  The longer form evaluates left to right
     examining only the first element of each vector.
     Evaluation proceeds only until the result is deter-
     mined.  The longer form is appropriate for programming
     control-flow.

     `xor' indicates elementwise exclusive OR.

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

     `TRUE' or `logical'.

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

     y <- 1 + (x <- rpois(50, lambda=1.5) / 4 - 1)
     x[(x > 0) & (x < 1)]    # all x values between 0 and 1
     if (any(x == 0) || any(y == 0)) "zero encountered"

