简单XML - 如何选择具有特定属性值的所有元素

Question

用户可以选择一个性能，以便性能元素具有唯一的ID。我想基本上说：

选择所有保留 - >预订['座位']从演出 - >表演['id = 2']。

希望这是有道理的，我真的很努力与简单的XML选择。

在此先感谢，亨利。

<performances> 
       <performance id="7" time="12:00" day="Monday" month="June" year="2010"> 
        <reservations> 
         <reservation seat="a7"/> 
         <reservation seat="a2"/> 
         <reservation seat="a3"/> 
        </reservations> 
       </performance> 
       <performance id="8" time="12:00" day="Tuesday" month="June" year="2010"> 
        <reservations> 
         <reservation seat="a8"/> 
        </reservations> 
       </performance> 
</performances> 

额外的信息：

我目前正在使用：echo $xml2->show->performances->performance['0']->reservations->reservation['seat']

这得到一个预约从第一次演出，但我想从性能上都保留有“3”例如ID 。

Answer 1

你的 “SQL”：

SELECT reservations->reservation['seat'] FROM performances->performance['id=2'] 

可以被改写为：

FROM performances->performance['id=2'] SELECT reservations->reservation['seat'] 

可以重新为XPath的：

 
//performances/performance[@id=2]/reservations/reservation/@seat 

蚂蚁这就是你所需要的。看看SimpleXML's xpath() method。

Answer 2

<?php 
// create a variable repsresenting the xml to parse through 
$string = '<performances> 
      <performance id="7" time="12:00" day="Monday" month="June" year="2010"> 
       <reservations> 
        <reservation seat="a7"/> 
        <reservation seat="a2"/> 
        <reservation seat="a3"/> 
       </reservations> 
      </performance> 
      <performance id="8" time="12:00" day="Tuesday" month="June" year="2010"> 
       <reservations> 
        <reservation seat="a8"/> 
       </reservations> 
      </performance> 
</performances>'; 

// create a variable representing a SimpleXMLElement instance 
$xml = simplexml_load_string($string); 

// create a variable representing the desired results, using the xpath method for 
// the SimpleXMLElement instance previously created. 
$results = $xml->xpath('//performances/performance[@id=2]/reservations/reservation/@seat'); 

?> 

对不起，偷Tomalak的雷声在这里。有些人需要它有时拼写出来。