- array_map: documentation ( source)
<?php
$user_meta = Array ( 'interest' => array(), 'type' =>
array(), 'user_status' => array('deny'),
'firstname' => array(), 'lastname' => array('B'),
'email' => 'email@cc.com');
$names = array_map(
function($person) { return $person[0]; },
$user_meta
);