Flatten multidimensional array PHP - php

Question

I need to flatten a PHP array but having some issues getting the desired results.
Array
(
[0] => Array
(
[case_code_id] => 1
[parent_id] => 0
[case_code] => Main A
[sub_codes] => Array
(
[0] => Array
(
[case_code_id] => 3
[parent_id] => 1
[case_code] => Sub A
[sub_codes] => Array
(
[0] => Array
(
[case_code_id] => 5
[parent_id] => 3
[case_code] => Sub Sub A
[sub_codes] => Array
(
)
)
)
)
[1] => Array
(
[case_code_id] => 4
[parent_id] => 1
[case_code] => Sub B
[sub_codes] => Array
(
)
)
)
)
[1] => Array
(
[case_code_id] => 2
[parent_id] => 0
[case_code] => Main B
[sub_codes] => Array
(
)
)
)
But I would like to convert this to the following:
Array
(
[0] => Array
(
[case_code_id] => 1
[parent_id] => 0
[case_code] => Main A
)
[1] => Array
(
[case_code_id] => 3
[parent_id] => 1
[case_code] => Sub A
)
[2] => Array
(
[case_code_id] => 5
[parent_id] => 3
[case_code] => Sub Sub A
)
[3] => Array
(
[case_code_id] => 4
[parent_id] => 1
[case_code] => Sub B
)
[4] => Array
(
[case_code_id] => 2
[parent_id] => 0
[case_code] => Main B
[sub_codes] => Array
)
I have tried several loops but nothing returns the full array.
Here is what I have for my loop:
public function array_flatten($array,$list=array()){
for ($i=0;$i<count($array);$i++) {
$results[] = array(
'case_code_id'=>$array[$i]['case_code_id'],
'case_code'=>$array[$i]['case_code'],
'parent_id'=>$array[$i]['parent_id']
);
if (count($array[$i]['sub_codes']) > 0) {
$this->array_flatten($array[$i]['sub_codes'],$results);
} else {
$results[] = $array[$i];
}
}
return $results;
}
And I'm calling it like this: ($multi contains the multidimensional array)
$flat = $this->array_flatten($multi);
The variable $multi is created from this function:
public function build_case_code_tree(array $elements, $parentId = 0) {
$branch = array();
foreach ($elements as $element) {
if ($element['parent_id'] == $parentId) {
$children = $this->build_case_code_tree($elements, $element['case_code_id']);
$element['sub_codes'] = $children;
$branch[] = $element;
}
}
return $branch;
}
Any thoughts?

Answer 1

function array_flatten($a, $flat = []) {
$entry = [];
foreach ($a as $key => $el) {
if (is_array($el)) {
$flat = array_flatten($el, $flat);
} else {
$entry[$key] = $el;
}
}
if (!empty($entry)) {
$flat[] = $entry;
}
return $flat;
}
print_r(array_flatten($multi));

Answer 2

You're not using $list anywhere in the code, and nothing is passed by reference.
You're close, but your function should use $list in the place of $results, and it should receive $list by reference and modifying it in place instead of returning it.
Something like this (untested though):
function array_flatten($array,&$list=array()){
for ($i=0;$i<count($array);$i++) {
$list[] = array(
'case_code_id'=>$array[$i]['case_code_id'],
'case_code'=>$array[$i]['case_code'],
'parent_id'=>$array[$i]['parent_id']
);
if (count($array[$i]['sub_codes']) > 0) {
$this->array_flatten($array[$i]['sub_codes'],$list);
} else {
$list[] = $array[$i];
}
}
}
And calling it like this:
$flat = Array();
$this->array_flatten($multi, $flat);
// Result is inside $flat now