too long

For example a multidimensional array like an example below

$arr = array(

 [H1] => array(
            "name" => "A"
            "title" => "T1"
      )
 [H2] => array(
           "name" => "B"
           "title" => "B1"
      )
)

Let's say I would like to search name which equals to A in $arr and if it's matched, the searching should return the key which is H1

How can I do that in php ?

I tried array_keys($arr, "A") but it returns me with an array instead of the key.

This may help -

$arr = array(

 'H1' => array(
            "name" => "A",
            "title" => "T1",
      ),
 'H2' => array(
           "name" => "B",
           "title" => "B1",
      )
);

// Generate a new array with 'keys' and values in 'name'
$new = array_combine(array_keys($arr), array_column($arr, 'name'));

// Search in that new array
$search = array_search('A', $new);

var_dump($search);

Output

string(2) "H1"

Demo

Another simple way would be -

$serach= false;
foreach($arr as $key => $val) {
   if($val['name'] == 'A') {
       $search= $key;
       break;
   }
}
var_dump($search);