PHP가 DOM을 기반으로 책 XML 형식 데이터를 읽는 방법에 대한 자세한 설명

<?php
 $doc = new DOMDocument();
 $doc->load( &#39;books.xml&#39; );
 $books = $doc->getElementsByTagName( "book" );
 foreach( $books as $book )
 {
 $authors = $book->getElementsByTagName( "author" );
 $author = $authors->item(0)->nodeValue;
 $publishers = $book->getElementsByTagName( "publisher" );
 $publisher = $publishers->item(0)->nodeValue;
 $titles = $book->getElementsByTagName( "title" );
 $title = $titles->item(0)->nodeValue;
 echo "$title - $author - $publisher\n";
 }
?>

<?xml version="1.0"?>
<books>
 <book>
  <author>Jack Herrington</author>
  <title>PHP Hacks</title>
  <publisher>O&#39;Reilly</publisher>
 </book>
 <book>
  <author>Jack Herrington</author>
  <title>Podcasting Hacks</title>
  <publisher>O&#39;Reilly</publisher>
 </book>
</books>

PHP Hacks - Jack Herrington - O'Reilly
Podcasting Hacks - Jack Herrington - O'Reilly