PHP实现正则匹配操作的方法

<?php
$str = <<< EOT
        <a href="www/app/a/2QRN7v" rel="external nofollow" >
          <p class="phonebg">
            @@##@@
            <p class="phoneclick"></p>
            <p>幸福领地</p>
          </p>
        </a>
        <a href="www/app/a/uqARNv" rel="external nofollow" >
          <p class="phonebg">
            @@##@@
            <p class="phoneclick"></p>
            <p>一世情长</p>
          </p>
        </a>
EOT;
if(preg_match_all('%<p.*?>(.*?)</p>%si', $str, $matches)) {
  $arr[0][] = $matches[1];
}
if(preg_match_all('/src="([^<]*)" >/i', $str, $matches)) {
  $arr[1][] = $matches[1];
}
print_r($arr);
exit;
?>

Array
(
  [0] => Array
    (
      [0] => Array
        (
          [0] => 幸福领地
          [1] => 一世情长
        )
    )
  [1] => Array
    (
      [0] => Array
        (
          [0] => http://www/template9/yunqingjian/jianjie/68.jpg
          [1] => http://www/template9/yunqingjian/jianjie/69.jpg
        )
    )
)