use warnings;
use strict;
use Benchmark qw/cmpthese/;

use List::Util qw/shuffle/;

my @numbers = ( 0..20 );
my @indices = shuffle 0..$#numbers;

my @expect = ( 0..2,4..20 );
use constant TEST => 0;

cmpthese(-2, {
	splice => sub {
		my @output = @numbers;
		for my $index (@indices){
			splice @output, 0, 1;
		}
		join("\0", @output) eq join("\0", @expect) or die if TEST;
	},
	grep => sub { # https://www.perlmonks.org/?node_id=11123877
		my @output;
		for my $index (@indices){
			@output = @numbers[ grep $_ != $index, 0 .. $#numbers ];
		}
		join("\0", @output) eq join("\0", @expect) or die if TEST;
	},
	hash => sub {
		my %ha; @ha{0..$#numbers} = @numbers;
		for my $index (@indices){
			delete $ha{$index};
		}
		my @output = map { $ha{$_} } sort keys %ha;
		join("\0", @output) eq join("\0", @expect) or die if TEST;
	},
});

__END__

           Rate   grep   hash splice
grep    30916/s     --   -85%   -96%
hash   205775/s   566%     --   -71%
splice 707918/s  2190%   244%     --