PHP排序3维数组

Question

I know this would be an easy one but I don't get it. All answered I found on the net was... too complex to me, maybe.

Here is my typical array:

array(
(int) 0 => array(
    'Conversation' => array(
        'id' => '1',
        'created' => '2012-08-04 00:00:00'
    ),
    'ConversationUser' => array(
        (int) 0 => array(
            'id' => '1'
        ),
        (int) 1 => array(
            'id' => '2'
        )
    )
),
(int) 1 => array(
    'Conversation' => array(
        'id' => '2',
        'created' => '2012-08-01 00:00:00'
    ),
    'ConversationUser' => array(
        (int) 0 => array(
            'id' => '1'
        ),
        (int) 1 => array(
            'id' => '2'
        )
    )
));

I want to sort my data with ['Conversation']['created'] date, asc or desc.

Any simple answer ? :P

PS I can't use MYSQL sort, I retrieve the data one by one and create that array.

Answer 1

Use usort() :

usort($your_array, function($a, $b){
    $a = strtotime($a['Conversation']['created']);
    $b = strtotime($b['Conversation']['created']);

    if ($a == $b) {
        return 0;
    }
    return ($a > $b) ? -1 : 1;
});

Answer 2

You can use array_multisort to do this:

// $data is your array from the example
// first obtain the rows for sorting
$sortkeys = array();
foreach ($data as $row) {
    $sortkeys[] = $row['Conversation']['created'];
}

// sort $data according to $sortkeys
array_multisort($sortkeys, $data);
var_dump($data);

Answer 3

You should have a look to uksort() and usort() functions, which let you customize the way arrays are sorted.

Either the solution is simple or complex, remember what Einstein said once: " Things should be always done as simple as possible, but never simpler than they really are ".

If you have some trouble with these functions, we can give you further clues ;-)

Answer 4

You can use usort() (or, to maintain index association, uasort() . Example: (assumes your array is $arr ):

usort($arr, function($a, $b) {
    return
    preg_replace('/\D/', '', $b['Conversation']['created'])
    >
    preg_replace('/\D/', '', $a['Conversation']['created']);
});

That will sort descending. Change > to < for ascending.