$ perl -MBenchmark=cmpthese -e'cmpthese( 2e6, {
ri=>sub{return int @_},
rs=>sub{return scalar @_},
rz=>sub{return 0+@_},
i=>sub{int@_},
s=>sub{scalar@_},
z=>sub{0+@_}})'
            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
            (warning: too few iterations for a reliable count)
         Rate   rz   ri    z   rs    i    s
rz 14285714/s   -- -21% -21% -43% -43% -57%
ri 18181818/s  27%   --  -0% -27% -27% -45%
z  18181818/s  27%   0%   -- -27% -27% -45%
rs 25000000/s  75%  37%  37%   --   0% -25%
i  25000000/s  75%  37%  37%   0%   -- -25%
s  33333333/s 133%  83%  83%  33%  33%   --