uasort is removing keys/arrays - php

Question

I'm trying to sort a multidimensional array (in fact that it is multidimensional doesn't matter since I'm always only sorting one dimension).
function orderSort($a, $b) {
if ($a['order'] == $b['order']) return 0;
return($a['order'] < $b['order']) ? -1 : 1;
}
$nav = array(
"section" => array(
"header" => array(),
"main" => array()
),
"link" => array(
"header" => array(),
"main" => array()
)
);
$DATA = array(
array(
"type" => "section",
"subtype" => "main",
"data" => array("name" => "/Basic", "order" => 1, "parent" => "bbb")
),
array(
"type" => "link",
"subtype" => "main",
"data" => array("name" => "Home", "link" => array("/"), "order" => 1, "parent" => "/Basic")
)
);
foreach($DATA as $ele) {
if(!array_key_exists($ele['data']['parent'], $nav[$ele['type']][$ele['subtype']]))
$nav[$ele['type']][$ele['subtype']][$ele['data']['parent']] = array($ele['data']);
else
array_push($nav[$ele['type']][$ele['subtype']][$ele['data']['parent']], $ele['data']);
}
var_dump($nav['section']['main']);
echo '<br><br>';
foreach($nav['section']['main'] as $ele) {
uasort($ele, 'orderSort');
$nav['section']['main'] = $ele;
}
var_dump($nav['section']['main']);
The first var_dump returns:
array(1) {
["bbb"]=> array(1) {
[0]=> array(3) {
["name"]=> string(6) "/Basic"
["order"]=> int(1) ["parent"]=> string(3) "bbb"
}
}
}
As you can see there is a key named bbb (Sorry for that... highly conceptional). Now the second output:
array(1) {
[0]=> array(3) {
["name"]=> string(6) "/Basic"
["order"]=> int(1)
["parent"]=> string(3) "bbb"
}
}
Suddenly bbb is gone. In fact the whole array (with only a single element) has disappeared.
My question is, can I somehow prevent this from happening? I never asked for this kind of of optimization. Of course sorting this with only one element doesn't make any sense but still.

Answer 1

foreach($nav['section']['main'] as $ele) {
uasort($ele, 'orderSort');
$nav['section']['main'] = $ele;
}
Okay. And which is the key? you just forgot the keys (you are overwriting the parent of the original array with a new array instead of the original array itself):
foreach($nav['section']['main'] as $key => $ele) {
uasort($ele, 'orderSort');
$nav['section']['main'][$key] = $ele;
}
would be correct, but by reference is even better:
foreach($nav['section']['main'] as &$ele) {
uasort($ele, 'orderSort');
}

Answer 2

Your problem is here:
foreach($nav['section']['main'] as $ele) {
uasort($ele, 'orderSort');
$nav['section']['main'] = $ele;
}
This needs to be
foreach($nav['section']['main'] as $index => $ele) {
uasort($ele, 'orderSort');
$nav['section']['main'][$index] = $ele;
}
You were replacing the whole $nav['section']['main'] with the first element.