How do I use PHP function array_push() in 2 Dimensional array?

I tried to find a simple answer of following question, but failed.

I have a 2D array and an 1D array:

$arr_2D = array(
    array("product" => "apple", "quantity" => 2),
    array("product" => "Orange", "quantity" => 4),
    array("product" => "Banana", "quantity" => 5),
    array("product" => "Mango", "quantity" => 7)
);

$element = array("product" => "Lemon", "quantity" => 9);

I wish to push 1D array into 2D array, and get a new and big 2D array:

$arr_2D = array(
    array("product" => "apple", "quantity" => 2),
    array("product" => "Orange", "quantity" => 4),
    array("product" => "Banana", "quantity" => 5),
    array("product" => "Mango", "quantity" => 7),
    array("product" => "Lemon", "quantity" => 9)
);

I tried:

$arr_2D = array_push($arr_2D, $element);

and not work.

How and Can I use function array_push?

Solution

Is this what you want ? both array_push() and the shorthand [] notation will add the $element array to the end of the $arr_2D array :

$arr_2D = array(
    array("product" => "apple", "quantity" => 2),
    array("product" => "Orange", "quantity" => 4),
    array("product" => "Banana", "quantity" => 5),
    array("product" => "Mango", "quantity" => 7)
);

$element = array("product" => "Lemon", "quantity" => 9);

//using array_push()
array_push($arr_2D, $element);

//using shorthand notation
$arr_2D[] = $element;

//printing the updated 2D array
print_r($arr_2D);

output :

Array
(
    [0] => Array
        (
            [product] => apple
            [quantity] => 2
        )

    [1] => Array
        (
            [product] => Orange
            [quantity] => 4
        )

    [2] => Array
        (
            [product] => Banana
            [quantity] => 5
        )

    [3] => Array
        (
            [product] => Mango
            [quantity] => 7
        )

    [4] => Array
        (
            [product] => Lemon
            [quantity] => 9
        )
)