代码不完全解析数据

Question

我有以下代码，看看wolfram阿尔法xml数据，并拉出围绕在<plaintext>标签中的答案。它适用于第一个标签，但不适用于答案之后。

代码：

<?php 
$url = "http://api.wolframalpha.com/v2/query?input=what+day+is+today&appid=9QA6R9-VGL4AAURHU&format=plaintext&podtitle=Result"; 

$ch = curl_init(); 
curl_setopt($ch, CURLOPT_URL, $url); 
ob_start(); 
curl_exec($ch); 
curl_close($ch); 
$contents = ob_get_contents(); 
ob_end_clean(); 
echo $contents; 

下面是答案，我得到：

Monday, May 3, 2011</plaintext> 
    </subpod> 
</pod> 
<sources count='2'> 
    <source url='http://www.wolframalpha.com/sources/AstronomicalDataSourceInformationNotes.html' 
     text='Astronomical data' /> 
    <source url='http://www.wolframalpha.com/sources/PeopleDataSourceInformationNotes.html' 
     text='People data' /> 
</sources> 
</queryresult> 

Answer 1

试试这个：

<?php 
$url = "http://api.wolframalpha.com/v2/query?input=what+day+is+today&appid=9QA6R9-VGL4AAURHU&format=plaintext&podtitle=Result"; 

$ch = curl_init(); 
curl_setopt($ch, CURLOPT_URL, $url); 
ob_start(); 
curl_exec($ch); 
curl_close($ch); 
$contents = ob_get_contents(); 
ob_end_clean(); 

function get($a,$b,$c){ 
    $y = explode($b,$a); 
    $x = explode($c,$y[1]); 
    return $x[0]; 
} 

echo get($contents,'<plaintext>','</plaintext>'); 
?>