David Gelpi Fleta's List: XPATH

• Selecting Nodes

   

  XPath uses path expressions to select nodes in an XML document.
• Expression  Description    nodename  Selects all child nodes of the named node    /  Selects from the root node    //  Selects nodes in the document from the current node that   match the selection no matter where they are     .  Selects the current node    ..  Selects the parent of the current node    @  Selects attributes

• Predicates

   

  Predicates are used to find a specific node or a node that contains a  specific value.

• Predicates are always embedded in square brackets.
• [1]
• [last()]
• [position()<3]
• [@lang]
• [@lang='eng']
• [price>35.00]
• Wildcard  Description    *  Matches any element node    @*  Matches any attribute node    node()  Matches any node of any kind

• Selecting Several Paths

   

  By using the | operator in an XPath expression you can select several paths.

    

10 more annotations...

• XPath Operators

• In XPath, there are seven kinds of nodes: element, attribute,  text, namespace, processing-instruction, comment, and document (root) nodes.
• XML documents are treated as trees of nodes. The root of the tree is called the  document node (or root node).

• Atomic values

   

  Atomic values are nodes with no children or parent.

• Children

   

  Element nodes may have zero, one or more children.

• Relationship of Nodes

   

  Parent

   

  Each element and attribute has one parent.

• Siblings

   

  Nodes that have the same parent.

• Ancestors

   

  A node's parent, parent's parent, etc.

• Descendants

   

  A node's children, children's children, etc.

6 more annotations...

• XPath is a language for finding information in an XML document

• What is XPath?

   
   
  • XPath is a syntax for defining parts of an XML document  
  • XPath uses path expressions to navigate in XML documents  
  • XPath contains a library of standard functions  
  • XPath is a major element in XSLT  
  • XPath is a W3C recommendation