call_user_func_array with array_multisort

Question

I have the problem with sort direction. I try to sort multi-dimensional array with direction. I can't use array_multisort() directly, because I don't know how many parametrs will be. I use call_user_func_array('array_multisort', $params); And it works, but I can't set sort direction (SORT_ASC,SORT_DESC). How can I set sort direction for call_user_func_array('array_multisort', $params);? Here is my code, you can try it

function get_fields($data, $order_by) {
    $order_row = preg_split("/[\s,]+/", $order_by);
    for ($i=0;$i<count($order_row);$i++) {
        foreach ($data as $key => $row) {
          $tmp[$i][$key]  = $row[$order_row[$i]];      
        }
    }
    return $tmp;
}

function ordering($data, $order_by) {
    $tmp = get_fields($data, $order_by);
    $params = array();
    foreach($tmp as &$t){
        $params[] = &$t;
    }

    $params[1] = array("SORT_DESC","SORT_DESC","SORT_DESC","SORT_DESC"); // like that no warning but no sorting

    $params[] = &$data;
    call_user_func_array('array_multisort', $params);
    return array_pop($params);
}

$data = array (
    array('id' => 1,'name' => 'Barack','city' => 9),
    array('id' => 7,'name' => 'boris','city' => 2),
    array('id' => 3,'name' => 'coris','city' => 2),
    array('id' => 3,'name' => 'coris','city' => 2)
);

$order_by = "city desc, name";

echo "<br>ORDER BY $order_by<br>";
$ordered = ordering($data, $order_by);
echo "<pre>";
var_dump($ordered);
echo "</pre>";

I want to do a sort like MySQL ORDER BY city DESC, name. It's my goal.

Answer 1

I had the same problem. It seems that call_user_func_array() can't handle the constants. I've solved this problem by dynamically building an argument string and evaluating this string:

$args  = array($arr1, $arr2);
$order = array(SORT_ASC, SORT_DESC);
$evalstring = '';

foreach($args as $i=>$arg){
    if($evalstring == ''){ $evalstring.= ', '; }
    $evalstring.= '$arg';
    $evalstring.= ', '.$order[$i];
}
eval("array_multisort($evalstring);");

I know eval() is evil and this is not a clean way, but it works ;-)