替代正则表达式获取xml标记的内容

Question

I'm processing a XML file and I need to get all content inside <section> tags.

Right now I'm using this regex:

<?php preg_match_all('/<section[^>]*>(.*?)<\/section>/i', $myXmlString, $results);?>

The code inside the <section> tags is pretty complex. It include math equations and stuff like that. In my local machine the regex works perfect. It is php 5.3.10 over apache 2.2.22 (Ubuntu)

BUT in my staging server it doesn't work. It is php 5.3.3 over apache 2.2.15 (Red Hat)

I would ask 2 questions:

Is there any issue with preg_match_all for php 5.3.3?

Is there a better way to express the regex?

--EDIT: VARIATIONS OF REGEX USED UNSUCCESSFULY--

<?php preg_match_all('/<section[^>]*>(.*?)<\/section>/is', $myXmlString, $results);?>
<?php preg_match_all('/<section[^>]*>(.*?)<\/section>/ims', $myXmlString, $results);?>
<?php preg_match_all('#<section[^>]*>(.*?)<\/section>#ims', $myXmlString, $results);?>
<?php preg_match_all('#<section[^>]*>([^\00]*?)<\/section>#ims', $myXmlString, $results);?>

--EDIT: Why haven't I used a parser?

The XML consists of two <sections>. Each section groups n questions for an exam.

Each question can include math equations represented by its own XML. An equation may be something like this:

<inlineequation><m:math baseline="-16.5" display="inline" overflow="scroll"><m:mrow><m:mtable columnalign="left"><m:mtr><m:mtd><m:mrow><m:mo stretchy="true">[</m:mo><m:mrow><m:mtable columnalign="right"><m:mtr><m:mtd><m:mn>4</m:mn></m:mtd><m:mtd columnalign="right"><m:mrow><m:mo>-</m:mo><m:mn>9</m:mn></m:mrow></m:mtd><m:mtd columnalign="right"><m:mrow><m:mn>54</m:mn></m:mrow></m:mtd></m:mtr><m:mtr><m:mtd columnalign="right"><m:mrow><m:mo>&minus;</m:mo><m:mn>28</m:mn></m:mrow></m:mtd><m:mtd columnalign="right"><m:mo>&minus;</m:mo><m:mn>1</m:mn></m:mtd><m:mtd columnalign="right"><m:mo>&minus;</m:mo><m:mn>14</m:mn></m:mtd></m:mtr></m:mtable></m:mrow><m:mo stretchy="true">]</m:mo></m:mrow></m:mtd></m:mtr></m:mtable></m:mrow></m:math></inlineequation>

I need that code to remain XML (no array) because I will pass that code as it is to a jQuery plugin which will render the equation (it will look like LaTeX equations).

If I parse the XML it will be really difficult to create the string for the equation again and locate it in the right place inside the question's statement.

Answer 1

regex can be resource intensive.

perhaps consider using xml_parse_into_struct;

<?php
    $xmlp = xml_parser_create();
    xml_parse_into_struct($xmlp, $myXmlString, $vals, $index);
    xml_parser_free($xmlp);
    print_r($vals);
?>