Refactor foreach with multilevel array - php

Question

I'm currently returning results from a sql statement in an array like so:
$results = [];
foreach($promotionTool as $p){
$results[] = $p;
}
return $results;
Which my console shows in an object with this structure:
(2) [{…}, {…}]
0:
codeID: "41"
code: "123ABC"
rule_type: "Category"
attribute_type: "identifier"
attribute_title: "category number"
attribute_value: "234"
1:
codeID: "41"
code: "123ABC"
rule_type: "Category"
attribute_type: "amount"
attribute_title: "percent"
attribute_value: "25"
This is showing the data I expect but I'm a little bit lost on how to restructure this so that I can group on certain levels and finally return only an array of the attributes like so:
codeID
code
rule_type
array(
0:
attribute_type: "identifier"
attribute_title: "category number"
attribute_value: "234"
1:
attribute_type: "amount"
attribute_title: "percent"
attribute_value: "25"
)
How would I refactor my foreach to group at multiple levels in that way?

Answer 1

I guess this is what you are looking for:
<?php
$input = [
[
'codeID' => "41",
'code' => "123ABC",
'rule_type' => "Category",
'attribute_type' => "identifier",
'attribute_title' => "category number",
'attribute_value' => "234"
],
[
'codeID' => "41",
'code' => "123ABC",
'rule_type' => "Category",
'attribute_type' => "amount",
'attribute_title' => "percent",
'attribute_value' => "25"
]
];
$output = [];
array_walk($input, function ($e) use (&$output) {
$output[$e['codeID']][$e['code']][$e['rule_type']][] = [
'attribute_type' => $e['attribute_type'],
'attribute_title' => $e['attribute_title'],
'attribute_value' => $e['attribute_value']
];
});
print_r($output);
This could be a variant easier to read:
array_walk($input, function ($e) use (&$output) {
$codeID = &$e['codeID'];
$code = &$e['code'];
$rule_type = &$e['rule_type'];
$output[$codeID][$code][$rule_type][] = [
'attribute_type' => $e['attribute_type'],
'attribute_title' => $e['attribute_title'],
'attribute_value' => $e['attribute_value']
];
});
The output obviously is:
Array
(
[41] => Array
(
[123ABC] => Array
(
[Category] => Array
(
[0] => Array
(
[attribute_type] => identifier
[attribute_title] => category number
[attribute_value] => 234
)
[1] => Array
(
[attribute_type] => amount
[attribute_title] => percent
[attribute_value] => 25
)
)
)
)
)