#!/usr/bin/perl

use strict;
use warnings;

use Benchmark qw( cmpthese );

my @c = 1 .. 1_000_000;

cmpthese( -3, {
   for => sub {
      my @e;
      for my $c ( @c ) {
         my $d = $c % 2;
         push @e, $d if !$d;
      }
   },

   for2 => sub {
      my @e;
      for my $c ( @c ) {
         push @e, 0 if !( $c % 2 );
      }
   },

   map_grep => sub {
      my @e =
         grep !$_,
            map $_ % 2,
               @c;
   },

   map => sub {
      my @e =
         map $_ % 2 ? () : 0,
            @c;
   },

   grep_x => sub {
      my @e = ( 0 ) x grep !( $_ % 2 ), @c;
   },

   grep_for => sub {
      my @e; push @e, 0 for 1 .. grep !( $_ % 2 ), @c;
   },
} );