thinkphp 正则表达式分组替换

<?php 

   8:     $filename = "C:\test.properties"; 

   9:     $mode = "r"; 

  10:     $file_handle = fopen($filename, $mode); 

  11:     $lineNum = 0; 

  12:     $pattern = "/{\d}[^{}]+/"; 

  13:     if ($file_handle) { 

  14:         while (!feof($file_handle)) { 

  15:             ++$lineNum; 

  16:             $line = fgets($file_handle); 

  17:             if (preg_match($pattern, $line)) { 

  18:                 $line = preg_replace("/{\d}/", "<font color='red'>$0</font>", $line); 

  19:                 echo "行".$lineNum."：".$line."<br/><br/><br/>"; 

  20:             } 

  21:         } 

  22:     } else { 

  23:         echo "文件读取失败"; 

  24:     } 

  25:     fclose($file_handle); 

  26: ?>