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<?php $arr = [ "Jan 12 02:08:23 hello", "Dec 23 21:37:56 hello", //"Jan 12 02:08:23 hello", //"Jan 16 17:34:33 hello", "Feb 4 12:21:09 hello", "Mar 19 17:07:26 hello", "Apr 1 00:00:03 hello", "Nov 10 11:00:03 hello", "Apr 12 23:07:39 hello", "May 21 04:09:34 hello", "Jun 7 23:34:56 hello", "Sep 29 07:36:03 hello", "Jul 1 14:45:34 hello", "Aug 13 11:37:23 hello", "Sep 29 07:36:03 hello", "Oct 30 09:01:00 hello", "Nov 10 11:00:03 hello", "Dec 25 21:47:51 hello" ]; var_export( preg_replace_callback( '/^([a-z]{3}) +\d+/i', function($m) { static $lastMonthInt = 0; static $year = null; $year ??= date('Y', strtotime('-1 year')); $currentMonthInt = date('n', strtotime($m[1])); if ($currentMonthInt < $lastMonthInt) { ++$year; } $lastMonthInt = $currentMonthInt; return "$year " . date('m d', strtotime($m[0])); }, $arr ) );

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