PHP preg_match_all() not capturing subgroups

I'm trying to parse a Twitte开发者_开发问答r atom feed in PHP but am running into this strange issue. I'm calling preg_match_all with this regexp string:

"|<entry>.*<title>(.*)</title>.*<published>(.*)</published>.*</entry>|xsU"

It matches all the entries OK, but the captured subgroups title/published do not show up in the results (no arrays for the captured subgroups are created in the result object).

Now to the strange part, I try to capture the last bit as well:

"|<entry>.*<title>(.*)</title>.*<published>(.*)</published>(.*)</entry>|xsU"

And now the capturing works. I get the title and the published date and the large chunk of final data that I don't want.

I tried to add the non capturing string "?:" to the last subgroup but then capturing stopped working alltogether again.

So how do I capture the data I want, without having to capture the large chunk of unwanted data at the end?

I recommend you use DOM (or SimpleXML) for parsing RSS/Atom feeds. You will get way better results than with regular expressions.

Here's an example (using SimpleXML):

$rss_feed = file_get_contents('http://stackoverflow.com/feeds/question/4187945');
$sxml = new SimpleXMLElement($rss_feed);

$title = $sxml->entry[0]->title;
echo $title;