php比较两个嵌套数组并预测差异

Question

How find difference of the two array

// ARRAY 1

$a1 = array(
    "a1" => 1,
    "a3" => array(
        "a31" => 31
    ),
    "a4" => array(
        "a41" => 41
    ),
    "a5" => array(
        "a51" => 51,
        "a52" => 52
    )
);

// ARRAY 2
$a2 = array(
    "a1" => 1,
    "a2" => 2,
    "a3" => array(
        "a31" => 31,
        "a32" => array(
            "a321" => 321,
            "a322" => 322
        )
    ),
    "a4" => array(
        "a41" => 42
    ),
    "a5" => array(
        "a51" => 51,
        "a52" => 52
    )
);

array_diff function returns ==> Array ( )

But there is a lot of difference exist in the above two array variables.

example:

1. in ARRAY1 There is no key a2 but in ARRAY2 a2 is available.
2. ARRAY2 a3 contain nested array (one nested level ) but in ARRAY 2 contain two nested sub level.

So here i want to compare two array n-level (ie. nested array)

Answer 1

$results = array_diff(array_map('serialize',$a2),array_map('serialize',$a1));
$results = array_map('unserialize',$results);

echo '<pre>';
print_r($results);