组合多个多维数组

Question

I have a set of menu items, like this:

[
    [ "cat" => [ "subcat" => [ "subsubcat1" => $item]]],
    [ "cat" => [ "subcat" => [ "subsubcat2" => $item2]]],
    [ "cat" => [ "subcat2" => [ "subsubcat3" => $item3]]],
    [ "cat" => [ "subcat2" => [ "subsubcat3" => $item4]]],
    [ "cat2" => [ "subcat2" => [ "subsubcat3" => $item5]]],
];

And I wish to combine them like this:

[ 
    "cat" =>
    [
        "subcat" => [
            "subsubcat1" => [ $item ],
            "subsubcat2" => [ $item2 ],
        ],
        "subcat2" => [
            "subsubcat3" => [ $item3, $item4 ]
        ]
    ], 
    "cat2" => [
        "subcat2" => [
            "subsubcat3" => [ $item5 ]
        ]
    ]
];

So I can generate an xml structure like this:

<menu>
    <category id="cat">
        <category id="subcat2">
            <category id="subsubcat1">
                <menuitem name="{ $item['title'] }" />
            </category>
         </category>
        [...]
   </category>
</menu>

Maybe the 2nd step can be omitted by using DOM but I can't figure this out. I tried array_merge_recursive(...$items) but this will also spread the $item.

How can I merge these multidimenision arrays, when the last value is of the last nested array is another type ( a class in this case)? The keys can be overwritten (no duplicate subcat2 in this case, unless the parent differs), but the value in the last array ($item, $item2 etc) need to be appended.

Answer 1

This is a recursive function that will add items with that structure.

function addItem($item, &$category) {
   if (!is_array($item)) {
      $category[] = $item;
   } else {
      $value = reset($item);
      $key = key($item);
      addItem($value, $category[$key]);
   }
}

You can apply it over the outer array like this:

$menu = [];

foreach ($initial as $item) {
   addItem($item, $menu);
}