

   LLooggiiccaall OOppeerraattoorrss

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

   DDeessccrriippttiioonn::

        These operators act on logical vectors.

        `!' indicates logical negation (NOT).

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

        `xor' indicates elementwise exclusive OR.

   SSeeee AAllssoo::

        `TRUE' or `logical'.

   EExxaammpplleess::

        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"

