PHP正则表达式

<?php
	error_reporting(E_ALL); //报告所有错误，error_reporting(0)设置会忽略错误
        
        //与perl里面的正则类似，/****/i,//为正则表达式界定符，js也可这样表示	
	$regex = '/^http:\/\/([\w.]+)\/([\w]+)\/([\w]+)\.html$/i';
	$str = 'http://www.youku.com/show_page/id_ABCDEFG.html';
	$matches = array();
	
	if(preg_match($regex, $str, $matches)){
	    var_dump($matches);
	}
	
	echo "<br/>";
	$reg = '/(?<num>\d+)/i';
	$k = "asd33sdfds4434dsdfd2222";
	$m_array = array();
        //匹配所有的
	if(preg_match_all($reg, $k, $m_array))
	{
	   var_dump($m_array);
	}

    //将连续的数字替换为一个*
    $a = preg_replace('/(\d+)/i', '*', 'asd3343ddsf999dfdf000fff');
    echo "<br/>".$a;
    
   //用,.;符号分割字符
   $sv = preg_split('/[,\.;]/i', "aa,dd;xxx.sdsd");
   var_dump($sv);
  ?>