<?php

$array = array( 0 => 'aa', 1 => 'bbb', 2 => null, 3 => 'ddd', 4 => null);

$arrayf1 = array_filter($array, function($v){if(!empty($v)) return true;});
$arrayf2 = array_filter($array, function($v){return !empty($v);});
$arrayf3 = array_filter($array);

print_r($array);
print_r($arrayf1);
print_r($arrayf2);
print_r($arrayf3);