Rate     Map Foreach
Map     21.9/s      --    -43%
Foreach 38.6/s     76%      --

##</code><code>##

use strict;

use Benchmark ();

Benchmark::cmpthese(-10, {
   "Map"      => sub { my %hash = map{$_=>1} (1..10000); },
   "Foreach"  => sub { my %hash; $hash{$_} = 1 foreach (1..10000); },
   "Map-like" => sub { my @a; push(@a, $_, 1) foreach (1..10000);
                       my %hash = @a; },
})


__END__
           Rate Map-like      Map  Foreach
Map-like 21.5/s       --      -1%     -44%
Map      21.8/s       1%       --     -43%
Foreach  38.6/s      80%      77%       --