Question

What is common practice given the two xml formats? And how would you go about converting the first to the second format, regex? Should I have <subgroupones> there at all? Basically any <tags> that have no attributes except <global> should be deleted or if there is a more elegant way.

<global>
    <groupone name="bce">
        <subgroupones>
            <subsgroupone name="a" />
            <subsgroupone name="b" />
            <subsgroupone name="c" />
        </subgroupones>
    <groupone>
</global>

<global>
    <groupone name="bce">
            <subsgroupone name="a" />
            <subsgroupone name="b" />
            <subsgroupone name="c" />
    <groupone>
</global>

Answer 1

XML to XML conversion is almost always best handled by Stylesheet Transform (XSLT). PHP has built-in libraries for handling XSLT: http://php.net/manual/en/book.xslt.php

For example, here’s an XSLT that will copy only elements that have attributes (with the exception of <global> which is always included):

<?xml version="1.0"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
  <xsl:template match="global | @* | node()[@*]">
    <xsl:copy><xsl:apply-templates select="@* | node()"/></xsl:copy>
  </xsl:template>
</xsl:stylesheet>

Sample output (not sure yet how to remove that excess space):

<?xml version="1.0" encoding="UTF-8"?><global>
    <groupone name="bce">

            <subsgroupone name="a"/>
            <subsgroupone name="b"/>
            <subsgroupone name="c"/>

    </groupone>
</global>

You can experiment with this tool: http://xslttest.appspot.com/