正则表达式不适用于PHP + cURL

Question

I'm making a cURL request to take data from one page.
The returned HTML content is (view image below):

http://i.imgur.com/Sbhepbw.png

I want to filter the following content 'Saldo principal: R$ 27,50'.
I'm trying to do this with regular expression but the script is returning an empty array.

This is my code:

$content = getContent();
preg_match_all("/Saldo Principal: R\$ [0-9]{1,},[0-9]{1,}/i", $content, $result);
echo '<pre>';
print_r($result);

This is the result:

Array ( [0] => Array ( ) )

I tested this using a regular expression site and everything is ok. Why is not working with PHP?

http://i.imgur.com/dcV2VnC.png

Answer 1

Make use of DOMDocument Class.

$content = getContent();
$dom = new DOMDocument;
@$dom->loadHTML($content);
foreach ($dom->getElementsByTagName('p') as $tag) {
       $pcontent[]=$tag->nodeValue;
}
echo trim($pcontent[1]); //"prints" Saldo principal: R$ 27,50

or you could put it in a single line. Like this.

echo $dom->getElementsByTagName('p')->item(1)->nodeValue;

Answer 2

Inside a double quoted string the backslash is treated as an escape character. thus:

either you single quote:

preg_match_all('/Saldo Principal: R\\$ [0-9]{1,},[0-9]{1,}/i', $content, $result);

or double escape:

preg_match_all("/Saldo Principal: R\\\\$ [0-9]{1,},[0-9]{1,}/i", $content, $result);