Array.prototype.flat()

function flareout_array($array) {

    $return = [];

    array_walk_recursive($array,function ($x) use (&$return) {

        $return[] = $x;
    });
    return $return;
}

$a = [
        [
            [1, 2, 3], 
            [2, 3, 4]
        ],
        [
            [1, 2, 3], 
            [
                2, 
                3, 
                [
                    2, 
                    3, 
                    [22, 333, 444]
                    , 
                    4, 
                    88, 
                    99
                ], 
                4
            ]
        ],
            [
                [1, 2, 3], 
                [2, 3, 4]
            ],
];

echo "<pre>";
print_r(flareout_array($a));


输出如下: