PHP array_column - how to keep the keys?

Looking for the same solution and combine some tricks, I created this:

$userdb=Array
(
    "test1" => array
    (
        'uid' => '100',
        'name' => 'Sandra Shush',
        'url' => 'urlof100'
    ),
    "test2" => array
    (
        'uid' => '5465',
        'name' => 'Stefanie Mcmohn',
        'pic_square' => 'urlof100'
    ),
    "test3" => array
    (
        'uid' => '40489',
        'name' => 'Michael',
        'pic_square' => 'urlof40489'
    )
);

echo $key = array_search(
    40489,
    array_filter(
        array_combine(
            array_keys($userdb),
            array_column(
                $userdb, 'uid'
            )
        )
    )
);

Result is 'test3'.

Work in array numbers or named arrays.

I think this is the fastest way to keep keys without loops and iterations

array_diff(array_combine(array_keys($items), array_column($items, 'id')), [null])

The simplest and the most performant way is probably using

array_combine(array_keys($data), array_column($data, 0));

See if this could help

array_filter(array_combine(array_keys($items), array_column($items, 'id')));