XPath Axes)

XML instance document

We will use this XML document in the following example:

<?xml version="1.0" encoding="ISO-8859-1"?><bookstore><book>  <title lang="eng">Harry Potter</title>  <price>29.99</price></book><book>  <title lang="eng">Learning XML</title>  <price>39.95</price></book></bookstore>

XPath axis

The axis defines a node set relative to the current node.

Axis name	Result
Ancestor	Select all the ancestors of the current node (parent, grandfather, etc)
Ancestor-or-self	Select all the founders of the current node (parent, grandfather, etc.) and the current node itself
Attribute	Select all attributes of the current node
Child	Select all child elements of the current node.
Descendant	Select all descendant elements (child, sun, etc.) of the current node ).
Descendant-or-self	Select all descendant elements (child, sun, etc.) of the current node and the current node itself.
Following	Select all nodes after the end label of the current node in the document.
Namespace	Select All namespace nodes of the current node
Parent	Select the parent node of the current node.
Preceding	Select all nodes before the start label of the current node in the document.
Preceding-sibling	Select all peer nodes before the current node.
Self	Select the current node.

Location Path expression

The location path can be absolute or relative.

The absolute path starts with a forward slash (/), but the relative path does not. In either case, the path contains one or more steps, and each step is separated by a slash:

Absolute path:

/step/step/...

Relative Path:

step/step/...

Each step is calculated based on the nodes in the current node set.

Steps include:

Axis)

Define the tree relationship between the selected node and the current node

Node-test)

Recognizes nodes inside a certain axis

Zero or more predicates (predicate)

Further refine the selected node set

Step Syntax:

Axis name: node test [predicates]

Instance

Example	Result
Child: Book	Select the book nodes of all the child elements of the current node
Attribute: Lang	Select the lang attribute of the current node
Child ::*	Select all child elements of the current node
Attribute ::*	Select all attributes of the current node
Child: Text ()	Select all text subnodes of the current node
Child: node ()	Select All subnodes of the current node
Descendant: Book	Select All book descendants of the current node
Ancestor: Book	Select All book predecessors of the current node
Ancestor-or-self: Book	Select all the book predecessors of the current node and the current node (if this node is a book node)
Child: */child: Price	Select all price grandchildren of the current node.