How to arrange multiple arrays by a specific field - php

Question

I have an array that has multiple arrays inside it. I am trying to arrange those arrays from the amount of greatest to least new_sales. Here is the example of the array which goes on for about 40 arrays:
Array
(
[0] => Array
(
[Tech] => Array
(
[first_name] => Anthony
[last_name] => Bisignano
)
[0] => Array
(
[new_sales] => 21
[upgrades] => 2
)
)
[1] => Array
(
[Tech] => Array
(
[first_name] => Arnold
[last_name] => Ybanez
)
[0] => Array
(
[new_sales] => 5
[upgrades] => 0
)
)
The function I am trying to use is the following:
function aasort (&$techs, $key) {
$sorter=array();
$ret=array();
reset($techs);
foreach ($techs as $ii => $va) {
$sorter[$ii]=$va[$key];
}
asort($sorter);
foreach ($sorter as $ii => $va) {
$ret[$ii]=$techs[$ii];
}
$techs=$ret;
}
aasort($test,"new_sales");
AM I using this function wrong or is there another approach I should be taking?

Answer 1

There are sorting functions in PHP that support user-defined comparison methods. Code like this should help you get started with that.
function cmp($a, $b)
{
if ($a[0]['new_sales'] == $b[0]['new_sales']) {
return 0;
}
return ($a[0]['new_sales'] < $b[0]['new_sales']);
}
usort($data, "cmp");

Answer 2

In this case you probably want to use usort() such that you can define your sorting logic.
So something like this:
usort($array, function($a, $b) {
if ($a[0]['new_sales'] > $b[0]['new_sales']) {
return -1; // note we use -1 here because we want a reverse sort
} else if ($a[0]['new_sales'] < $b[0]['new_sales']) {
return 1;
} else {
return 0;
}
});