<?php
 
    $xmlstr = <<<EOF
<root>
   <!-- ... -->
   <B ID="444">
        <C></C>  
        <D>Anything</D>
        <E>
            <child1>foo</child1>
            <child2>data2</child2>
            <child3>data3</child3>
            <child4>data4</child4>
        </E>
    </B>
   <!-- ... -->
</root>
EOF;
 
	$xml = new SimpleXMLElement($xmlstr);
    $query = "//B[@ID = 444 and .//child2 = 'data2' and .//child4 = 'data4']";
    $result = $xml->xpath($query);
    $dirty = False;
 
    foreach ($result as $b) {
        $child2 = $b->xpath(".//child2")[0];
        $child4 = $b->xpath(".//child4")[0];
 
    	echo (string)$child2;
    	echo (string)$child4;
 
 
 
        $child2[0] = "Blabla";
        $child4[0] = "Blaaaaaaaa";
 
        $dirty = True;
    }
 
    if ($dirty) {
        // $xml->saveXML($File);
    }
 
    echo $xml->saveXML();
?>

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