$a = array('matches' => 
        array(
            '5' => array('weight' => 6),
            '15' => array('weight' => 6),
        )
    );

    $b = array('matches' => 
        array(
            '25' => array('weight' => 6),
            '35' => array('weight' => 6),
        )
    );

    $merge = array_merge($a, $b);

    print_r($merge);

Bu komut sonucu

Array
(
    [matches] => Array
        (
            [25] => Array
                (
                    [weight] => 6
                )

            [35] => Array
                (
                    [weight] => 6
                )

        )

)

Ama neden?

Ben sonuç bu oldu istiyorum:

Array
(
    [matches] => Array
        (
            [5] => Array
                (
                    [weight] => 6
                )

            [15] => Array
                (
                    [weight] => 6
                )
            [25] => Array
                (
                    [weight] => 6
                )

            [35] => Array
                (
                    [weight] => 6
                )

        )

)