Numeric Values in xml tag

I am trying to convert array to xml data in php. I am using xmlserializer pear package for this. My array is:

$arr=array(1000=>'name is john');

When I convert it to xml using this code:

options=array ('mode'=>'simplexml','addDecl'=>true,'indent'=>'      ','rootName'=>'names');
$serializer = new XML_Serializer($options);
$result = $serializer->serialize($arr);
if($result == true)
                $data=$serializer->getSerializedData();
echo $data;

I get following response:

<?xml version="1.0"?>
<names>name is john&l开发者_如何学Got;/names>

But I want this kind of response:

<?xml version="1.0"?>
<names>
    <1000>name is john</1000>
</names>

can anyone tell where my mistake is?

I guess this is because numeric values are not allowed element names in XML. However, if you really want to have "xml-style" output like above (beside it is not real xml) you must bypass the library and code it by hand. I think this will do it for you:

public function xml_encode($array, $tag = "root"){
    $result = '<'.$tag.'>';
    foreach($array as $key => $value){
        if(is_array($value)){
            $result.=xml_encode($value, $key);
        }else{
            $result .= '<'.$key.'>'.$value.'</'.$key.'>';
        }
    }
    $result .= '</'.$tag.'>';
    return $result;
}