荷物の配送について

//エラー処理 $kaisha = (!isset($_POST['kaisha'])) ? null : $kaisha = $_POST['kaisha']; $denpyou = (!isset($_POST['denpyou'])) ? null : $denpyou = $_POST['denpyou']; $submit = (!isset($_POST['submit'])) ? null : $submit = $_POST['submit']; //URL設定 $url['1'] = "http://jizen.kuronekoyamato.co.jp/jizen/servlet/crjz.b.NQ0010?id=".$denpyou; $url['2'] = "http://k2k.sagawa-exp.co.jp/p/web/okurijosearch.do?okurijoNo=".$denpyou; $url['3'] = "http://tracking.post.japanpost.jp/service/singleSearch.do?org.apache.struts.taglib.html.TOKEN=&searchKind=S002&locale=ja&SVID=&reqCodeNo1=".$denpyou; if (empty($denpyou)){ echo "Error! is empty denpyou number"; } else { header("Location: ".$url["$kaisha"]); } ?>