use strict;
use warnings;
use Benchmark ('timethese');

my $size = 10000;
my @stats = map { [ "a$_" => 0] } (0..$size);

sub rewrite_array {
    @stats = map { $_->[0] eq 'a3333' ? [$_->[0], $_->[1] + 1] : $_ } @stats;
}

sub loop {
    for my $item ( @stats ) {
        $item->[1]++ if $item->[0] eq 'a3333';
    }
}

sub void_array {
    map { $_->[0] eq 'a3333' ? [$_->[0], $_->[1] + 1] : $_ } @stats;
}

timethese (10000, {
    '1. Array neu erstellen    ' => \&rewrite_array,
    '2. Schleife ausformuliert ' => \&loop,
    '3. Array im leeren Kontext' => \&void_array,
});