Online PHP editor | output for KLbNf

<?php $showtimes = [ "2014-01-20 20:00:00", "2014-01-21 20:00:00", "2014-01-22 14:00:00", "2014-01-22 20:00:00", "2014-01-23 20:00:00", "2014-01-25 20:00:00", "2014-01-26 20:00:00", "2014-01-31 20:00:00", "2014-02-01 20:00:00" ]; // 20th-23rd Jan 8pm, 22nd Jan 2pm, 25th-26th Jan 8pm, 31st Jan - 1st Feb 8pm foreach ($showtimes as $showtime) { $dt = new DateTime($showtime); $thisDay = $dt->format('Y-m-d H:i:s'); $nextDay = (clone $dt)->modify('+1 day')->format('Y-m-d H:i:s'); if (!isset($ref[$thisDay])) { $ref[$nextDay] = $dt->format('jS M ga'); $result[] =& $ref[$nextDay]; continue; } // if same month if (str_contains($ref[$thisDay], $dt->format('M'))) { // inject day $ref[$thisDay] = preg_replace( '/[tdh]\b\K[^ ]*/', $dt->format('-jS'), $ref[$thisDay] ); } else { // inject day and month $ref[$thisDay] = preg_replace( '/ (?=[^ ]*$)/', $dt->format(' - jS M '), $ref[$thisDay] ); } $ref[$nextDay] =& $ref[$thisDay]; } echo implode(', ', $result);