Why is an array passed with an index instead of a value?

Question

PHP

Hello everyone , the task is to pass the value with the button with the Formaction attribute , I try through the name , but the controller swears that the variable came in an array , moreover, the debug shows that it came with an index . Please tell me what's wrong, thanks in advance

<td style="text-align: center;">
                            <a class="button">
                                <button id="but"  name="<?= $post['post_id']; ?>" formaction="<?=$postDelete;?>" >Удалить</button>
                            </a>
                        </td>

public function postDelete() {
        $this->load->model('instagram/instagram');
        $post_id = $this->request->post;
        d($post_id);
        $this->model_instagram_instagram->postDelete($post_id);
        $this->session->data['success'] = "Запись удалена!";
        $this->redirect($this->url->link('instagram/instagram', 'token=' . $this->session->data['token'], 'SSL'));
    }

Notice: Array to string conversion in /var/www/true-false.ru/data/www/misha.true-false.ru/admin/model/instagram/instagram.php on line 60Notice: Error: Unknown column 'Array' in 'where clause'
Error No: 1054
DELETE FROM oc_instpost WHERE post_id= Array in /var/www/true-false.ru/data/www/misha.true-false.ru/system/database/mysqliz.php on line 37

And here comes this

Debug: 
Array
(
    [1503810305041303572_1587990717] => 
)

Answer 1

You might need something like this:
and

// не знаю что вы за фреймворк используете, но примерно так
$post_id = $this->request->post('post_id');
// или так
$post_id = $this->request->post['post_id'];
// или даже так
$post = $this->request->post;
$post_id = $post['post_id'];