array_filter_isnt_null

<?php

/*
 *  loop
 */
$a;            // NULL undefined bla bla
$b = 'valami'; // akármi
$c = false;    // negatív boolean
$d = 0;        // null(a) :)
$e = ''        // üres string

$array_a = array( $a, $b, $c, $d, $e );
$array_b = array();

foreach ( $array_a as $val )
  if ( $val !== NULL )
    $array_b[] = $val;

print_r( $array_b );
// Array ([0] => valami [1] => [2] => 0 [3] => )

/*
 *  filter
 */
function isnt_null( $val ) { return !is_null( $val ); }

$a;            // NULL undefined bla bla
$b = 'valami'; // akármi
$c = false;    // negatív boolean
$d = 0;        // null(a) :)
$e = ''        // üres string

$array = array_values( array_filter(
           array( $a, $b, $c, $d, $e ), 'isnt_null' ) );
print_r( $array );
// Array ([0] => valami [1] => [2] => 0 [3] => )