XPATH多元素过滤器

//element[condition]

  <book>
   <title>Book 1</title>
   <author>Author 1</author>
   <price>10.00</price>
  </book>
  <book>
   <title>Book 2</title>
   <author>Author 2</author>
   <price>12.00</price>
  </book>
  <book>
   <title>Book 3</title>
   <author>Author 3</author>
   <price>8.00</price>
  </book>
</books>

//book[price > 10]

<book>
 <title>Book 2</title>
 <author>Author 2</author>
 <price>12.00</price>
</book>