how to add form validation rule in this script

Question

hello i've learned about codeigniter form validation and i see on this tutorial script form validation like this

private function _validate(){

        $data  = array();
        $data['error_string'] = array();
        $data['inputerror'] = array();
        $data['status'] = TRUE;

        if($this->input->post('post_nama') == ''){
            $data['inputerror'][] = 'post_nama';
            $data['error_string'][] = 'Nama harus diisi';
            $data['status'] = FALSE;
        } 

        if($this->input->post('post_jk') == ''){
            $data['inputerror'][] = 'post_jk';
            $data['error_string'][] = 'Jenis Kelamin harus diisi';
            $data['status'] = FALSE;
        } 

        if($this->input->post('post_alamat') == ''){
            $data['inputerror'][] = 'post_alamat';
            $data['error_string'][] = 'Alamat harus diisi';
            $data['status'] = FALSE;
        } 

        if($data['status'] === FALSE){
            echo json_encode($data);
            exit();
        }
    }

my question is, if i want to use limited_number or max_length in that script, where i can place it?

Answer 1

    if( validation ){
        $data['inputerror'][] = '';
        $data['error_string'][] = '';
        $data['status'] = FALSE;
    } 

添加自己的验证