Convert stdClass object to array in PHP

Question

I fetch post_id from postmeta as:

$post_id = $wpdb->get_results("SELECT post_id FROM $wpdb->postmeta WHERE (meta_key = 'mfn-post-link1' AND meta_value = '". $from ."')");

when i try print_r($post_id); I have array like this:

Array
(
    [0] => stdClass Object
        (
            [post_id] => 140
        )

    [1] => stdClass Object
        (
            [post_id] => 141
        )

    [2] => stdClass Object
        (
            [post_id] => 142
        )

)

and i dont know how to traverse it, and how could I get array like this

Array
(
    [0]  => 140


    [1] => 141


    [2] => 142

)

Any idea how can I do this?

Answer 1

The easiest way is to JSON-encode your object and then decode it back to an array:

$array = json_decode(json_encode($object), true);

Or if you prefer, you can traverse the object manually, too:

foreach ($object as $value) 
    $array[] = $value->post_id;