php和xpath - 循环遍历特定元素的子元素

问题描述：

I would like to loop through each book_list in the following xml file and for each book_list loop through each book for that book_list.

<inventory>
    <book_list>
        <book>
            <author>Rowling</author>
            <title>Harry Potter</title>
        </book>
        <book>
            <author>Blyton</author>
            <title>Famous 5</title>
        </book>
    </book_list>
    <book_list>
        <book>
            <author>Bloggs</author>
            <title>Learning XML</title>
        </book>
        <book>
            <author>Jones</author>
            <title>Beginning PHP</title>
        </book>
    </book_list>
</inventory>

How can I, for each book_list, loop through each book, using xpath in a php simplexml script? Here is my code,

$booklistpath = $xml->xpath('//booklist');

foreach ($booklistpath as $booklist) {
    $bookpath = $xml->xpath('//book');
    foreach ($bookpath as $book) {
        ...
    }
}

The first loop is fine, it goes through each book_list - but the nested loop, which is meant to go through each book for that particular book_list goes through each book in the entire document. I have also tried :-

'.//book'  and 
'descendant::book'

我想循环遍历以下xml文件中的每个book_list，并为每个book_list循环遍历该book_list的每本书。 p>

 ＆lt; inventory＆gt; 
＆lt; book_list＆gt; 
＆lt; book＆gt; 
＆lt; author＆gt; Rowling＆lt; / 作者＆gt; 
＆lt; title＆gt;哈利波特＆lt; / title＆gt; 
＆lt; / book＆gt; 
＆lt; book＆gt; 
＆lt; author＆gt; Blyton＆lt; / author＆gt; 
＆lt; title＆gt; Famous 5＆lt; / title＆gt;  
＆lt; / book＆gt; 
＆lt; / book_list＆gt; 
＆lt; book_list＆gt; 
＆lt; book＆gt; 
＆lt; author＆gt; Bloggs＆lt; / author＆gt; 
＆lt; title＆gt;学习XML＆lt; / title＆gt; \  n＆lt; / book＆gt; 
＆lt; book＆gt; 
＆lt; author＆gt; Jones＆lt; / author＆gt; 
＆lt; title＆gt;从PHP开始＆lt; / title＆gt; 
＆lt; / book＆gt; 
＆lt; / book_list＆gt; \  n＆lt; / inventory＆gt; 
  code>  pre> 
 
 我怎样才能 book_list，循环遍历每本书，在php simplexml脚本中使用xpath？ 这是我的代码， p> 
 
 
  $ booklistpath = $ xml-＆gt; xpath（'// booklist'）; 
 
foreach  （$ booklistpath as $ booklist）{
 $ bookpath = $ xml-＆gt; xpath（'// book'）; 
 foreach（$ bookpath as $ book）{
 ... 
} 
} \  n  code>  pre> 
 
 第一个循环很好，它遍历每个 book_list  code>  - 但是嵌套循环，意味着要经过每个 该特定 book_list  code>的书籍 code>遍历整个文档中的每本书。 我也尝试过： -   p> 
 
 
 '。book book and 
'descendant :: book'
  code>  pre> 
  div  >

答

That's the right result since you're using the second xpath call on the original $xml which is the SimpleXMLElement for your whole XML document.

To get the books for each booklist just iterate them as follow:

$booklists = $sxe->xpath('//book_list');

foreach ($booklists as $booklist) {
    foreach ($booklist->book as $book) {
        echo $book->asXML();
    }
}

php和xpath - 循环遍历特定元素的子元素

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