PHP求解

<!DOCTYPE HTML PUBLIC"-//W3C//DTD HTML 4.01 Transitional//En">
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <title>例题1</title>
    </head>
    <body>
        <?php
        // 使用PHP显示当天的日期
        echo"<h2>今天是：";
        print date("Y")."年".date("m")."月".date("d")."日";
        $week= array("星期日","星期一","星期二","星期三","星期四","星期五","星期六");
        print $week[data("w")]."</h2>";
        ?>
    </body>
</html>
急！！！！求高手指点呀
php