Question

I have this string :

0=&task=rose&duration=1.25&user=15&1=&task=daisy&duration=0.75&user=25&2=&task=orchid&duration=1.15&user=7

I want this array structure :

array(
    array( "task" => "rose", 
           "duration" => 1.25,
           "user" => 15 
         ),
    array( "task" => "daisy", 
           "duration" => 0.75,
           "user" => 25,
         ),
    array( "task" => "orchid", 
           "duration" => 1.15,
           "user" => 7 
         )
      )

Answer 1

Now parse_url won’t work for your case, as it will overwrite the duplicate entries. You have to manually extract and group here.

$str = 'decoded_name=0=&task=rose&duration=1.25&user=15&1=&task=daisy&duration=0.75&user=25&2=&task=orchid&duration=1.15&user=7';
preg_match_all('#(\w+)=([^&=]*)(?:&|$)#', $str, $matches, PREG_SET_ORDER); 

$result = array();
$i = 0;    
foreach ($matches as $m) {
    list(, $key, $value) = $m;

    if (!strlen($value)) { 
       $i = (int)$key;
    }
    else {
       $result[$i][$key] = $value;
    }
}

The trick is watching out for the numeric keys (sans value), which separate your groups. The loop will generate following nested array:

[0] => Array
    (
        [task] => rose
        [duration] => 1.25
        [user] => 15
    )

[1] => Array
    (
        [task] => daisy
        [duration] => 0.75
        [user] => 25
    )

[2] => Array
    (
        [task] => orchid
        [duration] => 1.15
        [user] => 7
    )