use strict;  
use warnings;

use Benchmark 'cmpthese';

my $nums1 = join(",", 1..100);
my $nums2 = "1..100";

cmpthese(-1, {
    for1 => "my \$sum=0; foreach ($nums1) {\$sum++}",
    for2 => "my \$sum=0; foreach ($nums2) {\$sum++}",
    for3 => "my \$sum=0; \$sum++ foreach ($nums1)",
    for4 => "my \$sum=0; \$sum++ foreach ($nums2)",
    map1 => "my \$sum=0; map {\$sum++} $nums1",
    map2 => "my \$sum=0; map {\$sum++} $nums2",
    map3 => "my \$sum=0; map  \$sum++, $nums1",
    map4 => "my \$sum=0; map  \$sum++, $nums2",
});
 
__END__
        Rate map1 map3 map2 map4 for1 for3 for2 for4
map1 33185/s   --  -3%  -5%  -5%  -9% -17% -25% -34%
map3 34296/s   3%   --  -1%  -2%  -6% -15% -22% -32%
map2 34795/s   5%   1%   --  -0%  -5% -13% -21% -31%
map4 34909/s   5%   2%   0%   --  -5% -13% -21% -31%
for1 36571/s  10%   7%   5%   5%   --  -9% -17% -27%
for3 40193/s  21%  17%  16%  15%  10%   --  -9% -20%
for2 43997/s  33%  28%  26%  26%  20%   9%   -- -12%
for4 50243/s  51%  46%  44%  44%  37%  25%  14%   --