如何使用PHP查明数组中是否存在键值？

I have a question I need to find if the value of key in an array is existed in PHP and get the index value of it.

Example I have this array:

Array
(
    [0] => Array
        (
            [restaurant_id] => 1519
            [new_lat] => 14.63807
            [new_long] => 121.03158
            [date_updated] => 2013-11-14 16:40:34
        )

    [1] => Array
        (
            [restaurant_id] => 1247
            [new_lat] => 14.63877
            [new_long] => 121.03265
            [date_updated] => 2013-11-14 16:48:41
        )

)

I also used this code also:

$key = array_search($data_add['restaurant_id'],$data);

But it doesn't display the searched value

Now I need to fint if restaurant_id '1247' is existed in array? If existed get that index. Meaning get the index 1 because ID 1247 is in index 1.

I used the array_key_exists() but it will find the key not the key value. I hope you can help me thanks.

Try this:

$myArray = []; // Array as above
$target = '1247';

for ($i=0; $i<count($myArray);$i++) {
    if ($myArray[$i]['restaurant_id'] == $target) {
        break;
    }
}
// $i contains index of target