目前，它在页面上显示5条新闻。但我想显示20条新闻，也许更多。我怎么能用PHP改变这一点。提前感谢所有支持的人。

$perpage = $this->input->get('_pp') ? $this->input->get('_pp') :PERPAGE_5;
        $this->page = $this->input->get('per_page') ? intval($this->input->get('per_page')) : 0;
        $this->data->numOfContent = $this->news->getNews(false,false,TRUE);
        $this->link = site_url() . '/' . $this->urlString . '?_pp=' . $perpage;
        $this->data->news      = $this->news->getNews($perpage,$this->page);