XPath examples

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XPath examples
Output of xpath-examples.php:
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XPath is like a file system
/books/book/title
-----------
<title>Apache Web-Server</title>
--
<title>Linux fÃ¼r Internet und Intranet</title>
--
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// matches all nodes, which fullfill the following criteria
//title
-----------
<title>Apache Web-Server</title>
--
<title>Linux fÃ¼r Internet und Intranet</title>
--
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The star * selects all nodes on that level
/books/book/*
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<title>Apache Web-Server</title>
--
<year>2000</year>
--
<dc:subject>Webserver</dc:subject>
--
<title>Linux fÃ¼r Internet und Intranet</title>
--
<year>2000</year>
--
<dc:subject>Operating Systems</dc:subject>
--
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Square brackets can further specifiy the nodes
/books/book[1]
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<book id="1" isbn="3-8266-0612-4">
    <title>Apache Web-Server</title>
    <year>2000</year>
    <dc:subject>Webserver</dc:subject>
  </book>
--
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The last book
/books/book[last()]
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<book id="2" isbn="3-8266-0550-0">
    <title>Linux fÃ¼r Internet und Intranet</title>
    <year>2000</year>
    <dc:subject>Operating Systems</dc:subject>
  </book>
--
-----------
Attributes are prefixed by a @
/books/book/@isbn
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 isbn="3-8266-0612-4"
--
 isbn="3-8266-0550-0"
--
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Values of attributes can be used as selection criteria.
/books/book[@id = 2]
-----------
<book id="2" isbn="3-8266-0550-0">
    <title>Linux fÃ¼r Internet und Intranet</title>
    <year>2000</year>
    <dc:subject>Operating Systems</dc:subject>
  </book>
--
-----------
with count() the resulting nodes can be counted
 (does not work with query()) 
count(//books)
-----------
-----------
name() returns the node name
//*[name() = 'title']
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<title>Apache Web-Server</title>
--
<title>Linux fÃ¼r Internet und Intranet</title>
--
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Several paths can be combined with | separator.
//title | //year
-----------
<title>Apache Web-Server</title>
--
<year>2000</year>
--
<title>Linux fÃ¼r Internet und Intranet</title>
--
<year>2000</year>
--
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The descendant axis contains the descendants of the context node
/books/descendant::*
-----------
<book id="1" isbn="3-8266-0612-4">
    <title>Apache Web-Server</title>
    <year>2000</year>
    <dc:subject>Webserver</dc:subject>
  </book>
--
<title>Apache Web-Server</title>
--
<year>2000</year>
--
<dc:subject>Webserver</dc:subject>
--
<book id="2" isbn="3-8266-0550-0">
    <title>Linux fÃ¼r Internet und Intranet</title>
    <year>2000</year>
    <dc:subject>Operating Systems</dc:subject>
  </book>
--
<title>Linux fÃ¼r Internet und Intranet</title>
--
<year>2000</year>
--
<dc:subject>Operating Systems</dc:subject>
--
-----------
The parent axis contains the parent of the context node
/books/book[position() = 1]/title/parent::*
-----------
<book id="1" isbn="3-8266-0612-4">
    <title>Apache Web-Server</title>
    <year>2000</year>
    <dc:subject>Webserver</dc:subject>
  </book>
--
-----------
The following-sibling axis contains all the following siblings of the context node.
/books/book[position() = 1]/title/following-sibling::*
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<year>2000</year>
--
<dc:subject>Webserver</dc:subject>
--
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contains() checks, if a node contains the needle
//book[contains(dc:subject,"System")]
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<book id="2" isbn="3-8266-0550-0">
    <title>Linux fÃ¼r Internet und Intranet</title>
    <year>2000</year>
    <dc:subject>Operating Systems</dc:subject>
  </book>
--
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starts-with() checks, if a node starts with the needle
//book[contains(dc:subject,"Operating")]
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<book id="2" isbn="3-8266-0550-0">
    <title>Linux fÃ¼r Internet und Intranet</title>
    <year>2000</year>
    <dc:subject>Operating Systems</dc:subject>
  </book>
--
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