XML learning notes (6): How to Use XPath-Basic Concepts

Document directory

• Processing node Nodes functions
• Returns a Boolean function.
• Function for processing string Strings
• Function for processing numeric Numbers

• Location path: path, which is equivalent to the path of a file in the file system. XML documents contain many elements and attributes. The Location of nodes, elements, and attributes specified according to the XPath syntax rules in the XML document is Location path.
• Axis: similar to the disk symbol used by our file path, for example, C: \, D :\. Axis positions other parts of the XML file based on the current node position. Some elements may be located before or after the current node, which forms the separation of XML documents. The commonly used Axis is shown in the following table.

• Node tests: checks the element or Node type based on certain conditions and returns the selected element or Node.
• Predicates: A boolean expression used to return true or false results based on the limited Axis, node, or element, and the specified condition.

Example:

Following: employee [@ employeeid = '2']

Axis: Node test [Predicates]

Description: The employee ID attribute of the current node is 2.

// Employee [./firstname/text () = 'some _ text']

Meaning: whether the text string of the firstname node of the current node employee node under the root node (//) meets the 'some _ text' Condition
// Employee [@ employeeid = '1']

Description: The value of the employeeid attribute of the root node (//) is 1.

XPath built-in functions process node Nodes functions

Returns a Boolean function.

Function for processing string Strings

Function for processing numeric Numbers

Related Resources:

Http://www.cnblogs.com/xiaofanabc/archive/2005/04/20/141132.html

Http://www.cnblogs.com/xiaofanabc/archive/2005/04/20/141327.html