PHP simplexml_load_string不加载

I'm trying to use simplexml_load_string like so:

$xml = '<?xml version="1.0" encoding="utf-8"?>
<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <soap:Body>
    <data_GetResult xmlns="http://api.source.com/">
      <data_GetData>
        <value>123456</value>
        <value>789000</value>
      </data_GetData>
    </data_GetResult>
  </soap:Body>
</soap:Envelope>';      

$results = simplexml_load_string($xml);
print_r($results);

However, no results are returned, it simply shows:

SimpleXMLElement Object
(
)

I believe the xml is proper, I tested it in on-line validators. Thank you.

Try this (as per the manual)

<?php
$string = <<<XML
<?xml version="1.0" encoding="utf-8"?>
<soap_Envelope xmlns_xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns_xsd="http://www.w3.org/2001/XMLSchema" xmlns_soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap_Body>
<data_GetResult xmlns="http://api.source.com/">
<data_GetData>
<value>123456</value>
<value>789000</value>
</data_GetData>
</data_GetResult>
</soap_Body>
</soap_Envelope>  
XML;

$xml = simplexml_load_string($string);

print_r($xml);
?>

It seems as though the : in your names were (which is odd they seem part of the scheme) causing the problem e.g.

</soap:Body>
</soap:Envelope>