(PHP)正则表达式-贪婪匹配与懒惰匹配的区别

<?php/** * Created by PhpStorm. * User: Ollydebug * Date: 2015/11/15 * Time: 15:20 */$pattern = '/google.+123/';//$pattern = '/google.+123/';   修正匹配//$pattern = '/google.+123/U';  懒惰匹配$subject = 'I love google__123123123123123123';$matches = array();preg_match($pattern,$subject,$matches);show($matches);function show($var){    if(empty($var)){        echo 'null';    }elseif(is_array($var)||is_object($var)){        // array,object        echo '<pre>';        print_r($var);        echo '</pre>';    }else{        //string,int,float        echo $var;    }}?>