Recursive ksort : not sort the array - php

Question

I have a question
So I have this array :
Array
(
[2016] => Array
(
[23] => Array
(
[total_auctions] => 0
[total_price] => 0
)
[22] => Array
(
[total_auctions] => 0
[total_price] => 0
)
[21] => Array
(
[total_auctions] => 0
[total_price] => 0
)
[20] => Array
(
[total_auctions] => 0
[total_price] => 0
)
)
I want to sort recursive by key. So I create the methode :
public function sortNestedArrayAssoc($a)
{
if (!is_array($a)) {
return false;
}
ksort($a);
foreach ($a as $k=>$v) {
$this->sortNestedArrayAssoc($a[$k]);
}
return true;
}
But I get the same result, the array with the key 23 is the first and I don' really understand where is the problem. Can you help me please ? Thx in advance and sorry for my english

Answer 1

As John Stirling mentioned, something you could do would be to pass your arguments by reference. You can do this by using the & operator in your method argument. The syntax for that would be (with the only change being the first line):
public function sortNestedArrayAssoc(&$a)
{
if (!is_array($a)) {
return false;
}
ksort($a);
foreach ($a as $k=>$v) {
$this->sortNestedArrayAssoc($a[$k]);
}
return true;
}
This means that you are then passing the variable into your function and modifying it directly instead of what PHP does normally which is pass a copy of the variable into your function. ksort is an example of a function that uses a pass by reference in its function definition.
If you were strongly against using pass by reference, you'd have to modify your code to return your variable/array to the calling scope where you then update your array.
public function sortNestedArrayAssoc($a)
{
if (is_array($a)) {
ksort($a);
foreach ($a as $k=>$v) {
$a[$k] = $this->sortNestedArrayAssoc($v);
}
}
return $a;
}