function multi_diff($arr1,$arr2){
$result = array();
foreach ($arr1 as $k=>$v){
if(!isset($arr2[$k])){
$result[$k] = $v;
} else {
if(is_array($v) && is_array($arr2[$k])){
$diff = multi_diff($v, $arr2[$k]);
if(!empty($diff))
$result[$k] = $diff;
}
}
}
return $result;
}
//example:
var_dump(multi_diff(
array(
"A"=>array(
"A1"=>array('A1-0','A1-1','A1-2','A1-3'),
"A2"=>array('A2-0','A2-1','A2-2','A2-3'),
"A3"=>array('A3-0','A3-1','A3-2','A3-3')
),
"B"=>array(
"B1"=>array('B1-0','B1-1','B1-2','B1-3'),
"B2"=>array('B2-0','B2-1','B2-2','B2-3'),
"B3"=>array('B3-0','B3-1','B3-2','B3-3')
),
"C"=>array(
"C1"=>array('C1-0','C1-1','C1-2','C1-3'),
"C2"=>array('C2-0','C2-1','C2-2','C2-3'),
"C3"=>array('C3-0','C3-1','C3-2','C3-3')
),
"D"=>array(
"D1"=>array('D1-0','D1-1','D1-2','D1-3'),
"D2"=>array('D2-0','D2-1','D2-2','D2-3'),
"D3"=>array('D3-0','D3-1','D3-2','D3-3')
)
),
array(
"A"=>array(
"A1"=>array('A1-0','A1-1','A1-2','A1-3'),
"A2"=>array('A2-0','A2-1','A2-2','A2-3'),
"A3"=>array('A3-0','A3-1','A3-2')
),
"B"=>array(
"B1"=>array('B1-0','B1-2','B1-3'),
"B2"=>array('B2-0','B2-1','B2-2','B2-3'),
"B3"=>array('B3-0','B3-1','B3-3')
),
"C"=>array(
"C1"=>array('C1-0','C1-1','C1-2','C1-3'),
"C3"=>array('C3-0','C3-1')
),
"D"=>array(
"D1"=>array('D1-0','D1-1','D1-2','D1-3'),
"D2"=>array('D2-0','D2-1','D2-2','D2-3'),
"D3"=>array('D3-0','D3-1','D3-2','D3-3')
)
)
));