PHP正则表达式笔记与实例详解(5)

//正则匹配函数：preg_match preg_match_all
$str=<<<yfstr
 <div id="mainNav" class="clearfix">
  <a href="index.php" rel="external nofollow" >首页</a>
  <a href="category.php?id=3" rel="external nofollow" >GSM手机</a>
  <a href="category.php?id=4" rel="external nofollow" >双模手机</a>
  <a href="category.php?id=6" rel="external nofollow" >手机配件</a>
  <a href="group_buy.php" rel="external nofollow" >团购
  商品</a>
  <a href="activity.php" rel="external nofollow" >优惠活动</a>
  <a href="snatch.php" rel="external nofollow" >夺宝奇兵</a>
  <a href="auction.php" rel="external nofollow" >拍卖活动</a>
  <a href="exchange.php" rel="external nofollow" >积分商城</a>
  <a href="message.php" rel="external nofollow" >留言板</a>
  <a href="http://bbs.ecshop.com/" rel="external nofollow" >EC论坛</a>
 </div>
yfstr;
echo "<table width='900' border='1'>";
echo "<tr><th>名称</th><th>URL地址</th><th>链接</th></tr>";
//使用正则匹配
preg_match_all("/<a href=\"(.*?)\".*?>(.*?)<\/a>/s",$str,$a);
foreach($a[0] as $k=>$v){
 echo "<tr>";
 echo "<td>{$a[2][$k]}</td>";
 echo "<td>{$a[1][$k]}</td>";
 echo "<td>{$v}</td>";
 echo "</tr>";
}
echo "</table>";

<<<EOF
...
EOF;

$str="/<div id=\"mainNav\" class=\"clearfix\">/";

//正则的其他函数使用：
//preg_quote -- 转义正则表达式字符
//preg_split -- 用正则表达式分割字符串
//preg_replace -- 执行正则表达式的搜索和替换
//1.preg_quote -- 转义正则表达式字符
echo preg_quote("(abc){10}","'");//在每个增则表达式语法的字符前增加一个反斜杠
$s = "a{4}";
preg_match("/".preg_quote($s)."/","werta{4}yu",$a);
var_dump($a);
echo "<br/>";
//2. preg_split -- 用正则表达式分割字符串
$s = "12,34:56;784;35,67:897:65";
$list = preg_split("/[,:;]/",$s);
var_dump($list);
echo "<hr/>";
//3. preg_replace执行正则表达式的搜索和替换
$s = "12,34:56;784;35,67:897:65";
//要求将上面的:,;都换成空格
echo preg_replace("/[,;:]/"," ",$s);
$str = "<ul style='color:red'>
   <li>aaaaa</li>
   <li>bbbbb</li>
   <li>ddddd</li>
   <li>eeeee</li>
  </ul>";
//将上面字串中所有li标签中都添加一个b标签。
echo "<hr/>";
echo $str;
echo "<hr/>";
//echo preg_replace("/<li>(.*?)<\/li>/","<li><b>\\1</b></li>",$str);
//echo preg_replace("/<li>(.*?)<\/li>/","<li><b>\$1</b></li>",$str);
echo preg_replace("/<li>(.*?)<\/li>/",'<li><b>$1</b></li>',$str);