Php array sort by date after merge - php

Question

Hi i have an array which is combinations of 2 separate array producing same result, following are my array after merge :
Array
(
[0] => Array
(
[event_id] => 16
[user_id] => 3
[date_created] => 20130227095010
)
[1] => Array
(
[event_id] => 15
[user_id] => 2
[date_created] => 20130227101734
)
[2] => Array
(
[event_id] => 16
[user_id] => 2
[date_created] => 20130227094856
)
)
From here onwards how can i sort again based on date_created desc or asc without using previously 2 arrays which i used to merge?
Update:
previous array result
array1:
Array
(
[0] => Array
(
[event_id] => 15
[user_id] => 2
[date_created] => 20130227101734
)
[1] => Array
(
[event_id] => 16
[user_id] => 2
[date_created] => 20130227094856
)
)
array 2:
Array
(
[0] => Array
(
[event_id] => 16
[user_id] => 3
[date_created] => 20130227095010
)
)
How can i use loop within these function to extract date_created for each of above arrays
usort($array,function($a, $b) { return $a['date_created'] - $b['date_created']; });

Answer 1

Very easy with something like usort().
usort($array,
function($a, $b) { return $a['date_created'] - $b['date_created']; });

Answer 2

You can create your own sort function callback and use it with the usort method.
There is need to re-use your first 2 arrays.
usort($yourMergedArray, yourCallBackSort);
and
function yourCallBackSort($firstEntry, $secondEntry)
{
// Do some stuff to compare your values and return -1, 0 or 1
// depend if $firstEntry id <, = or > to $secondEntry
}

Answer 3

Try this,
$sort = array();
foreach($your_combined_array as $k=>$v) {
$sort['date_created'][$k] = $v['date_created'];
}
array_multisort($sort['date_created'], SORT_DESC, $your_combined_array);
echo "<pre>";
print_r($your_combined_array);