php and xpath - loop through child elements of particular element - php

Question

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'

Answer 1

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();
}
}