simplexml_load_string has a bug?

Question

when i use simplexml_load_string, i find a question, lose data, after use it.

$xml = '<dblp>
<inproceedings key="conf/aaim/He07" mdate="2007-06-28">
<author>Dan He</author>
<title>
<i>BMA</i>
<sup>*</sup>
: An Efficient Algorithm for the One-to-Some Shortest Path Problem on Road Maps.
</title>
<pages>346-357</pages>
<year>2007</year>
<crossref>conf/aaim/2007</crossref>
<booktitle>AAIM</booktitle>
<ee>http://dx.doi.org/10.1007/978-3-540-72870-2_33</ee>
<url>db/conf/aaim/aaim2007.html#He07</url>
</inproceedings>
</dblp>';
print_r(simplexml_load_string($xml));

running result:

  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
        )

)

where is the data ': An Efficient Algorithm for the One-to-Some Shortest Path Problem on Road Maps.'?
i hope xml to array.but data lost?thanks. i want the result:

Array
(
[0] => Array
(
    [inproceedings] =>Array
    (
        [author] => Dan He
        [title] => Array
        (
            [0] => BMA
            [2] => *
            [5] => : An Efficient Algorithm for the One-to-Some Shortest Path Problem on Road Maps.
        )

        [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
    )

)

)

Answer 1

The first rule of SimpleXMLElement is: you don't print_r() or var_dump() SimpleXMLElement Objects

As for why you can't see the information, see this note from the documentation:

Note: SimpleXML has made a rule of adding iterative properties to most methods. They cannot be viewed using var_dump() or anything else which can examine objects.

To access the title, you can do:

$xmlObj = simplexml_load_string($xml);
$title = (string) $xmlObj->inproceedings->title;

The properties of a SimpleXMLElement objects are objects themselves, so you need to cast them as strings by adding (string) at the beginning (or by using strval()). Now their values will be cast to a string instead of an object.

What should you use when you want to inspect SimpleXML objects?

You can use IMSoP's simplexml_dump() and simplexml_tree() helper functions. Here's the project on GitHub.