XML Feeds&PHP - 限制项目数量

Question

我正在浏览BBC新闻XML Feed.但我想要做的是限制它说8或10项饲料.

我怎样才能做到这一点？

我的代码是:

<?php

  $doc = new DOMDocument();
  $doc->load('http://feeds.bbci.co.uk/news/rss.xml');
  $arrFeeds = array();
  foreach ($doc->getElementsByTagName('item') as $node) {
    $itemRSS = array ( 
      'title' => $node->getElementsByTagName('title')->item(0)->nodeValue,
      'desc' => $node->getElementsByTagName('description')->item(0)->nodeValue,
      'link' => $node->getElementsByTagName('link')->item(0)->nodeValue,
      'date' => $node->getElementsByTagName('pubDate')->item(0)->nodeValue
      );
?>

<h2><a href="<?php echo $itemRSS['link'] ;?>"><?php echo $itemRSS['title']; ?></a></h2>
<?php  } ?>

提前致谢..

Answer 1

使用XPath,您可以轻松检索RSS提要的子集.

$itemCount = 10;
$xml = simplexml_load_file('http://feeds.bbci.co.uk/news/rss.xml');
$items = $xml->xpath(sprintf('/rss/channel/item[position() <= %d]', $itemCount));
foreach ($items as $i) {
    $itemRSS = array ( 
        'title' => (string)$i->title,
        'desc' => (string)$i->description,
        'link' => (string)$i->link,
        'date' => (string)$i->pubDate
    );
}

通过DOM对象交换对象,你会变得更轻一些SimpleXML- 而且XPath更容易使用SimpleXML(这就是我在这个例子中使用它的原因).同样可以通过以下方式实现DOM:

$doc = new DOMDocument();
$doc->load('http://feeds.bbci.co.uk/news/rss.xml');
$xpath = new DOMXpath($doc);
$items = $xpath->query(sprintf('/rss/channel/item[position() <= %d]', $itemCount));
foreach ($items as $i) {
    // ...
}

Answer 2

取一个计数器变量,每次迭代递增1,检查计数器是否达到上限,然后退出循环.

$cnt=0;
foreach ($doc->getElementsByTagName('item') as $node) {
    if($cnt == 8 ) {
       break;
     }    
    $itemRSS = array ( 
      'title' => $node->getElementsByTagName('title')->item(0)->nodeValue,
      'desc' => $node->getElementsByTagName('description')->item(0)->nodeValue,
      'link' => $node->getElementsByTagName('link')->item(0)->nodeValue,
      'date' => $node->getElementsByTagName('pubDate')->item(0)->nodeValue
      );
      $cnt++;
?>    
<h2><a href="<?php echo $itemRSS['link'] ;?>"><?php echo $itemRSS['title']; ?></a></h2>
<?php 
} ?>