PHP - 无键推送到数组

I'm trying to add some $_POST values to my $_SESSION array, but I can't seem to find the best approach.

Result with array_push():

array(1) {
  'product_ids' =>
  array(2) {
    [0] =>
    string(1) "9"
    [1] =>
    array(1) {
      [0] =>
      string(2) "14"
    }
  }
}

expected result:

array(1) {
  'product_ids' =>
  array(2) {
    [0] =>
    string(1) "9"
    [1] =>
    string(2) "14"
    }
  }
}

Code:

if(!empty($_SESSION['product_ids'])){
    array_push($_SESSION['product_ids'],$_POST['id']);
} else {
    $_SESSION['product_ids'] = $_POST['id'];
}

$_POST array:

array(1) {
  'id' =>
  array(1) {
    [0] =>
    string(2) "14"
  }
}

$_SESSION array:

Emtpy

If $_POST['id'] is an array of ids, it should be named $_POST['ids']. Use clear naming.

... else {
    $_SESSION['product_ids'] = $_POST['id'];

Initially you're creating $_SESSION['product_ids'] as an array…

if(!empty($_SESSION['product_ids'])){
    array_push($_SESSION['product_ids'],$_POST['id']);

…you're then pushing an array as value into the existing array. You want to merge those two arrays into a new array instead:

if (empty($_SESSION['product_ids'])) {
    $_SESSION['product_ids'] = $_POST['ids'];
} else {
    $_SESSION['product_ids'] = array_merge($_SESSION['product_ids'], $_POST['ids']);
}