使用时间戳对数组进行排序

Question

Im trying to create sort button for list but ive got this list, and i dont know what to do with this timestamp is it possible to sort with it, here is my array type, i hope you will help me guys here it it:

Array
(
    [0] => 17
    [ticket] => 17
    [1] => Name Second Name
    [author] => Name Second Name 
    [2] => modules
    [subject] => modules
    [3] => 1412335833
    [timestamp] => 1412335833
    [4] => 1414048041
    [activity] => 1414048041
    [5] => Closed
    [type] => Closed
    [6] => 3
    [priority] => 3
    [7] => 13
    [assignment] => 13
    [8] => 17
)

Array
(
    [0] => 18
    [ticket] => 18
    [1] => Name Second Name 
    [author] => Name Second Name
    [2] => modules
    [subject] => modules
    [3] => 1412335935
    [timestamp] => 1412335935
    [4] => 1414048095
    [activity] => 1414048095
    [5] => Closed
    [type] => Closed
    [6] => 3
    [priority] => 3
    [7] => 0
    [assignment] => 0
    [8] => 18
)

As you can see timestamp is the date. I need to sort it, here is what ive tried:

function date_compare($a, $b)
    {
        $t1 = strtotime($a['timestamp']);
        $t2 = strtotime($b['timestamp']);
        return $t1 - $t2;
    }    
    usort($row, 'date_compare');

But i get error because of timestamp... Here is error Warning: Illegal string offset 'timestamp' in /home/...../domains/foxiad.com/public_html/...../modules/ticketsmith/index.php on line 365

Answer 1

The output of array you are showing here looks generated by this kind of thing, which are all seperate arrays.

while($row = mysql_fetch_row($variable))
{
    print_r($row);
}

You need to build one seprate array, then perform a sort on it.

while($row = mysql_fetch_row($variable))
{
    $results[] = $row;
}

Then, you will be able to sort that, feeding $results to usort()