denormalization(?) of an array of items - php

Question

SOLVED
Im trying to denormalization (if this is the right word) an array of items.
Each item has a qty. And if an item has f.e. qty of 2 then i want to add the same item (a copy) qty-times (minus one because 1st is already there).
Example:
$items = [
[
'name' => 'Foo',
'qty' => 2,
'items' => [
[
'name' => 'Bar',
'qty' => 2,
'items' => [
[
'name' => 'Baz',
'qty' => 2,
'items' => [],
],
],
],
],
],
];
$expected = [
[
'name' => 'Foo',
'qty' => 1,
'items' => [
[
'name' => 'Bar',
'qty' => 1,
'items' => [
[
'name' => 'Baz',
'qty' => 1,
'items' => [],
],
[
'name' => 'Baz',
'qty' => 1,
'items' => [],
],
],
],
[
'name' => 'Bar',
'qty' => 1,
'items' => [
[
'name' => 'Baz',
'qty' => 1,
'items' => [],
],
[
'name' => 'Baz',
'qty' => 1,
'items' => [],
],
],
],
],
],
[
'name' => 'Foo',
'qty' => 1,
'items' => [
[
'name' => 'Bar',
'qty' => 1,
'items' => [
[
'name' => 'Baz',
'qty' => 1,
'items' => [],
],
[
'name' => 'Baz',
'qty' => 1,
'items' => [],
],
],
],
[
'name' => 'Bar',
'qty' => 1,
'items' => [
[
'name' => 'Baz',
'qty' => 1,
'items' => [],
],
[
'name' => 'Baz',
'qty' => 1,
'items' => [],
],
],
],
],
],
];
Script (recursive test):
function func(array $items, array &$r)
{
foreach ($items as $item) {
for ($i = 1; $i <= $item['qty']; $i++) {
echo "{$item['name']}\r\n";
func($item['items'], $r);
}
}
}
$r = [];
func($items, $r);
file_put_contents('tmp/_test.php', "<?php return\r\n" . var_export($r, true) . ";");
Out:
Foo
Bar
Baz
Baz
Bar
Baz
Baz
Foo
Bar
Baz
Baz
Bar
Baz
Baz
So far so good.
But i cant get the items correctly sorted into $r.
Thanks for any help.
Sorry. Solution came to my mind as i re.read my own post.
I was stuck in references. But i just should have returned the items array.
Working script:
function func(array $items)
{
$_items = [];
$n = 0;
foreach ($items as $item) {
for ($i = 1; $i <= $item['qty']; $i++) {
echo "{$item['name']}\r\n";
$_items[$n] = $item;
$_items[$n]['qty'] = 1;
$_items[$n]['items'] = func($item['items']);
$n++;
}
}
return $_items;
}
$r = func($items);
file_put_contents('tmp/_test.php', "<?php return\r\n" . var_export($r, true) . ";");

Answer 1

You can compact your solution and eliminate the $n counter.
I am starting $i from 0 so that only < is needed to maintain the logic.
I have used ++$i instead of $i++ as a micro-optimization.
I have renamed the function and variables because I found it a little confusing with the variable names being so similar and the function not being descriptive.
I tested this with 2,2,2, 2,0,2,, 1,2,3, and 3,2,1 and my changes have not damaged the result. I think this is as tight as I can make it.
Code: (Demo)
function expand(array $array){
$expanded=[];
foreach($array as $sub){
for($i=0; $i<$sub['qty']; ++$i){
$expanded[]=['name'=>$sub['name'],'qty'=>1,'items'=>expand($sub['items'])];
}
}
return $expanded;
}
$items = [
[
'name' => 'Foo',
'qty' => 2,
'items' => [
[
'name' => 'Bar',
'qty' => 2,
'items' => [
[
'name' => 'Baz',
'qty' => 2,
'items' => [],
],
],
],
],
],
];
var_export(expand($items));