使用simplexml按屬性選擇項目

Question

我想只選擇指定倉庫來更新庫存。 I.E.我想只有99，但是每個項目有不同數量的倉庫所以下面的代碼只能在99倉庫工作在第3行：

$quantity_calc = $this_product->stock[2]; 

這裏的示例XML：

<product sku="123546" supplier="BOSCH" price="1.71"> 
<stock warehouse="SAND">2.00</stock> 
<stock warehouse="44">2.00</stock> 
<stock warehouse="55">4.00</stock> 
<stock warehouse="77">2.00</stock> 
<stock warehouse="88">2.00</stock> 
<stock warehouse="97">2.00</stock> 
<stock warehouse="99">2.00</stock> 
<stock warehouse="33">2.00</stock> 
</product> 

和print_r的（$ this_product - >股票）;

[@attributes] => Array 
     (
      [warehouse] => SAND 
     ) 

    [0] => 2.00 
    [1] => 2.00 
    [2] => 4.00 
    [3] => 2.00 
    [4] => 2.00 
    [5] => 2.00 
    [6] => 2.00 
    [7] => 2.00 
) 

Answer 1

要獲取DOM的一部分，請使用Xpath表達式。 SimpleXMLElement::xpath()可以訪問它：

$product = new SimpleXMLElement($xml); 
var_dump(
    (string)$product->xpath('//stock[@warehouse=99]')[0] 
); 

DOM擴展本身已經爲它的DOMXpath類：

$document = new DOMDocument(); 
$document->loadXml($xml); 
$xpath = new DOMXpath($document); 

var_dump(
    $xpath->evaluate('string(//stock[@warehouse=99])') 
);