php simplexml_load_string 返回的对象print_r后，丢失信息？

<?php

$content = '<dblp>

<inproceedings key="conf/aaim/He07" mdate="2007-06-28">

<author>Dan He</author>

<title>

<i>BMA</i>

<sup>*</sup>

: An Efficient Algorithm for the One-to-Some Shortest Path Problem on Road Maps.

</title>

<pages>346-357</pages>

<year>2007</year>

<crossref>conf/aaim/2007</crossref>

<booktitle>AAIM</booktitle>

<ee>http://dx.doi.org/10.1007/978-3-540-72870-2_33</ee>

<url>db/conf/aaim/aaim2007.html#He07</url>

</inproceedings>

</dblp>';

$xml = simplexml_load_string($content);

print_r($xml);

　结果:

SimpleXMLElement Object

(

    [inproceedings] => SimpleXMLElement Object

        (

            [@attributes] => Array

                (

                    [key] => conf/aaim/He07

                    [mdate] => 2007-06-28

                )



            [author] => Dan He

            [title] => SimpleXMLElement Object

                (

                    [i] => BMA

                    [sup] => *

                )



            [pages] => 346-357

            [year] => 2007

            [crossref] => conf/aaim/2007

            [booktitle] => AAIM

            [ee] => http://dx.doi.org/10.1007/978-3-540-72870-2_33

            [url] => db/conf/aaim/aaim2007.html#He07

        )



)

　　在title中丢失了信息，因为返回的是一个迭代对象，具体查看http://stackoverflow.com/questions/21660547/simplexml-load-string-has-a-bug

。