#/usr/bin/perl

use warnings;
use strict;
use Benchmark qw(cmpthese);

my @arr = (0,3,4,5,8,10,12,15, 1..999999);

cmpthese (-2,
          {
        mapgrep => sub {map {$arr[$_]} grep {$_ & 1} 1..$#arr},
        slice => sub {@arr[ grep {$_ & 1} 1..$#arr ];},
        mult => sub {@arr[map {$_*2+1} 0..int(@arr/2)-1];},
        grep => sub {my $ind = 0; grep {$ind++ % 2} @arr},
        push => sub {my @var; push(@var, $arr[$_*2+1]) for 0..int(@arr/2)-1},
        map => sub {map { $arr[$_*2+1] } 0..int(@arr/2)-1},
        }
    );

##</code><code>##

~/perl$ cat /proc/version
Linux version 2.6.26.8-57.fc8 (mockbuild@x86-4.fedora.phx.redhat.com) (gcc version 4.1.2 20070925 (Red Hat 4.1.2-33)) #1 SMP Thu Dec 18 18:59:49 EST 2008
~/perl$ perl -v

This is perl, v5.8.8 built for x86_64-linux-thread-multi

~/perl$ perl ./everyother.pl
          Rate mapgrep   slice    push    mult    grep     map
mapgrep 5.24/s      --    -22%    -28%    -33%    -34%    -43%
slice   6.73/s     28%      --     -8%    -14%    -15%    -27%
push    7.28/s     39%      8%      --     -7%     -8%    -21%
mult    7.80/s     49%     16%      7%      --     -1%    -15%
grep    7.92/s     51%     18%      9%      1%      --    -14%
map     9.22/s     76%     37%     27%     18%     16%      --