Online PHP editor | output for OrL27

<?php $array = array ( 0 => array ( 'database' => 'oneclick_themes', 'disk_usage' => 16384, 'users' => array ( 0 => 'oneclick_themes' ), ), 1 => array ( 'database' => 'oneclick_wp1', 'disk_usage' => 123230, 'users' => array ( 0 => 'oneclick_wp1' ), ), 2 => array ( 'users' => array ( 0 => 'oneclick_wp10' ), 'database' => 'oneclick_wp10', 'disk_usage' => 123230 ), 3 => array ( 'users' => array ( 0 => 'oneclick_wp11' ), 'disk_usage' => 123222, 'database' => 'oneclick_wp11' ), 4 => array ( 'users' => array ( 0 => 'oneclick_wp12' ), 'disk_usage' => 123230, 'database' => 'oneclick_wp12' ), 5 => array ( 'users' => array ( 0 => 'oneclick_wp13' ), 'disk_usage' => 123222, 'database' => 'oneclick_wp13' ), 6 => array ( 'users' => array ( 0 => 'oneclick_wp14' ), 'database' => 'oneclick_wp14', 'disk_usage' => 123222 ), 7 => array ( 'users' => array ( 0 => 'oneclick_wp2' ), 'disk_usage' => 123226, 'database' => 'oneclick_wp2' ), 8 => array ( 'users' => array ( 0 => 'oneclick_wp3' ), 'disk_usage' => 0, 'database' => 'oneclick_wp3' ), 9 => array ( 'database' => 'oneclick_wp4', 'disk_usage' => 123230, 'users' => array ( 0 => 'oneclick_wp4' ), ), 10 => array ( 'users' => array ( 0 => 'oneclick_wp5' ), 'database' => 'oneclick_wp5', 'disk_usage' => 0 ), 11 => array ( 'users' => array ( 0 => 'oneclick_wp6' ), 'database' => 'oneclick_wp6', 'disk_usage' => 0 ), 12 => array ( 'disk_usage' => 123222, 'database' => 'oneclick_wp7', 'users' => array ( 0 => 'oneclick_wp7' ), ), 13 => array ( 'disk_usage' => 123222, 'database' => 'oneclick_wp8', 'users' => array ( 0 => 'oneclick_wp8' ), ), 14 => array ( 'database' => 'oneclick_wp9', 'disk_usage' => 0, 'users' => array ( 0 => 'oneclick_wp9' ), ) ); $wp_db_prefix = 'oneclick'; $max = max(array_map(function ($v) use ($wp_db_prefix) { return (int)str_replace("{$wp_db_prefix}_wp", '', $v); }, array_column($array, 'database'))) + 1; echo $max;