Валерий

$date_to = strtotime('2018-05-03 23:59:59');
$date_from = strtotime('2018-05-03 00:00:00');
for ($i = $date_from; $i <= $date_to; $i += 60 * 30){
     $aDinner[] = date('H:i', $i) . '-' . date('H:i', $i + 60 * 30);
}

preg_replace('/^(.*)\.(.*)$/U', 'replacement$2', 'thistrplase.noreplace');

$arr1 = [
    '04.02.2013-03.03.2013', 
    '04.03.2013-03.04.2013',
    '04.12.2013-03.01.2014',
    '04.01.2014-03.02.2014',
    '04.12.2014-03.01.2015',
    '04.01.2015-03.02.2015',
    '04.02.2015-03.03.2015',
];

$result = [];

foreach ($arr as $r) {
	$year = [];
	if (preg_match('/.[0-9]{4}/', $r, $year)) {
		$year = $year[0];
		if (!isset($result[$year]) {
			$result[$year] = [];
		}
		$result[$year][] = str_replace(".$year", '', $r);
	}
}