rearrange multidimensional array on basis of value of inner array - php

Question

i have an array like this
Array
(
[0] => Array
(
[cat_name] => Clothing
[cat_id] => 1
[item_name] => shirt
[item_id] => 1
[src] => 177
[sic] => 78
)
[1] => Array
(
[cat_name] => Stationary
[cat_id] => 3
[item_name] => note book
[item_id] => 8
[src] => 50
[sic] => 10
)
[2] => Array
(
[cat_name] => Stationary
[cat_id] => 3
[item_name] => ball pen
[item_id] => 10
[src] => 59
[sic] => 58
)
[3] => Array
(
[cat_name] => Expandable
[cat_id] => 4
[item_name] => vim powder
[item_id] => 14
[src] => 34
[sic] => 23
)
[4] => Array
(
[cat_name] => Clothing
[cat_id] => 1
[item_name] => pant
[item_id] => 16
[src] => 100
[sic] => 10
)
)
now what i want
first it sorted by cat_id and then a create a new array having below structure
Array
(
[0] =>"Clothing"=>Array
(
[0]=>Array
(
[item_name] => shirt
[item_id] => 1
[src] => 177
[sic] => 78
)
[1] => Array
(
[item_name] => pant
[item_id] => 16
[src] => 100
[sic] => 10
)
)
[1] => "Stationary"=>Array
(
[0] => Array
(
[item_name] => note book
[item_id] => 8
[src] => 50
[sic] => 10
)
[1] => Array
(
[item_name] => ball pen
[item_id] => 10
[src] => 59
[sic] => 58
)
)
[2]=>"Expandable => Array
(
[0] => Array
(
[item_name] => vim powder
[item_id] => 14
[src] => 34
[sic] => 23
)
)
)

Answer 1

Untested
$output = array();
foreach($array as $item) {
if(!isset($output[$item['cat_name']])) {
$output[$item['cat_name']] = array();
}
$catName = $item['cat_name'];
unset($item['cat_name']);
$output[$catName][] = $item;
}

Answer 2

function cmp($a, $b)
{
if ($a['cat_id'] == $b['cat_id']) {
return 0;
}
return ($a['cat_id'] < $b['cat_id']) ? -1 : 1;
}
// sort by cat_id
usort($array, 'cmp');
// create the grouped array
$res = array();
foreach($array as &$item) {
$cat_name = $item['cat_name'];
unset($item['cat_name'], $item['cat_id']);
$res[$cat_name][] = $item;
}