类stdClass的对象无法转换为int codeigniter

Question

I want to convert an integer value if I put intval() error again come

<?php
    $last = $this->db->select('pt_id')->order_by('pt_id',"desc")->limit(1)->get('patient_details')->row();
    //$myvar = (int)($last);
        print_r($last);
    ?>