fastest way to get parent array key in multidimensional arrays with php

Question

what is the best way to get parent array key with multidimensional arrays? for example I have this array:

array(

    [0] => array(0=> sample, 1=>picture, 2=>frame, 3=>google)

    [1] => array(0=> iphone, 1=>orange, 2=>love, 3=>msn)

    [2] => array(0=> joe, 1=>geee, 2=>panda, 3=>yahoo)
)

now I need to search for example google and get the parent array key.. which it should be 0...any ideas? I used for loop for this but I think it will be slow if I have arrays with 700000 rows..

Answer 1

If you have an array with 700,000 rows you are almost certainly doing something wrong... I would first recomend thinking about utilizing a different data store: flat file or some type of DB.

foreach($array as $key => $value) {
    if(in_array('google', $value)) return $key
}