How to unset or remove an array from a mult dimension array when you only know the key of the child but not the parent

Question

I am working on an indexing proj. its all fine up until when i have to udate the index file. i want whe a website is deleted by the admin, all its index posting lists should be deleted. please help by pointing me to the write way of removing an array from a mutlt dimensional array.

given an array like bellow, 3 is the id of the indexed website in the database. the admin deletes that website. I want also to be able to remove its posting references from my index.

Array
(
[mr] => Array
   (
        [3] => Array
            (
                [frequency] => 3
                [position] => Array
                    (
                        [0] => 16
                        [1] => 94
                        [2] => 110
                    )

            )

    )

[smith] => Array
    (
        [3] => Array
            (
                [frequency] => 3
                [position] => Array
                    (
                        [0] => 17
                        [1] => 95
                        [2] => 111
                    )

            )

    )
)

lets call that array $index. How can someone unset or delet all arrays that have a key of 3. meaning that i will be left with an array like this.

Array
(
[mr] => Array
(

 )

[smith] => Array
(

)
)

Answer 1

Very simple.

Loop through the first level array, and then loop through each second level array. If the second level key is 3, set the value at the first level array to be an empty array.

foreach($array as $key => $val) {
    foreach($val as $key2 => $val2) {
        if($key2 == 3) { unset($array[$key][$key2]); }
    }
}

Edited in response to below comment.