php array group by with key value

file.php

// Input
$data = array(
    array("name" => "John", "age" => 25),
    array("name" => "Jane", "age" => 22),
    array("name" => "Bob", "age" => 25),
    array("name" => "Sara", "age" => 22)
);

$groupedData = array_reduce($data, function($result, $item) {
    $result[$item['age']][] = $item;
    return $result;
}, array());

// Output
Array
(
    [25] => Array
        (
            [0] => Array
                (
                    [name] => John
                    [age] => 25
                )

            [1] => Array
                (
                    [name] => Bob
                    [age] => 25
                )

        )

    [22] => Array
        (
            [0] => Array
                (
                    [name] => Jane
                    [age] => 22
                )

            [1] => Array
                (
                    [name] => Sara
                    [age] => 22
                )

        )

)