如何在使用谷歌货币api与PHP时只获得结果值？

I'm using the "new" google currency calculator, and instead of the precedent version, now we have a form, with dropdown menus..etc, what i need is just to get the result value.

This is my simple php function :

    // GOOGLE CURRENCY CONVERTER API
function converter_currency($amount, $from){
    $result = file_get_contents('https://www.google.com/finance/converter?a='.$amount.'&from='.$from.'&to=USD');

    print_r ($result);
    // echo gettype($result); <== said that it's a string
}
  converter_currency(5, 'EUR'); //converts 5euros to USD

That returns a form ..ect with the result : 5 EUR = 5.4050 USD How to get only : 5.4050 ?

Thank you.

function converter_currency($amount, $from){
    $result = file_get_contents('https://www.google.com/finance/converter?a='.$amount.'&from='.$from.'&to=USD');
    preg_match('#\<span class=bld\>(.+?)\<\/span\>#s', $result, $finalData);
    return $finalData[1];
}

echo converter_currency(5, 'EUR'); // 5.4125 USD

list($amount, $currency) = explode(' ', converter_currency(5, 'EUR'));
var_dump($amount, $currency); // string(6) "5.4125" string(3) "USD"

function converter_currency($amount, $from, $to="USD"){
    $result = file_get_contents('https://www.google.com/finance/converter?a='.$amount.'&from='.$from.'&to='.$to);
    if($doc = @DomDocument::loadhtml($result)){
        if($xpath=new DomXpath($doc)){
            if($node = $xpath->query("//span")->item(0)){
                $result = $node->nodeValue;
                if($pos = strpos($result," ")){
                    return substr($result,0,$pos);
                }
            }
        }
    }
    return "Error occured";
}