SimpleXML和PHP:提取XML文档的一部分并将其转换为数组

Consider the following XML:

考虑下面的XML:

<?xml version="1.0" encoding="UTF-8"?>
<OS>
    <data>
        <OSes>
            <centos>
                <v_5>
                    <i386>
                        <id>centos5-32</id>
                        <name>CentOS 5 - 32 bit</name>
                        <version>5</version>
                        <architecture>32</architecture>
                        <os>centos</os>
                    </i386>
                    <x86_64>
                        <id>centos5-64</id>
                        <name>CentOS 5 - 64 bit</name>
                        <version>5</version>
                        <architecture>64</architecture>
                        <os>centos</os>
                    </x86_64>
                </v_5>
                <v_6>
                    <i386>
                        <id>centos6-32</id>
                        <name>CentOS 6 - 32 bit</name>
                        <version>6</version>
                        <architecture>32</architecture>
                        <os>centos</os>
                    </i386>
                    <x86_64>
                        <id>centos6-64</id>
                        <name>CentOS 6 - 64 bit</name>
                        <version>6</version>
                        <architecture>64</architecture>
                        <os>centos</os>
                    </x86_64>
                </v_6>
            </centos>
            <ubuntu>
                <v_10>
                    <i386>
                        <id>ubuntu10-32</id>
                        <name>Ubuntu 10 - 32 bit</name>
                        <version>10</version>
                        <architecture>32</architecture>
                        <os>ubuntu</os>
                    </i386>
                    <amd64>
                        <id>ubuntu10-64</id>
                        <name>Ubuntu 10 - 64 bit</name>
                        <version>10</version>
                        <architecture>64</architecture>
                        <os>ubuntu</os>
                    </amd64>
                </v_10>
            </ubuntu>
        </OSes>
    </data>
</OS>
<?xml