XPath

XPath

1. Predicates 谓语: written in square brackets

   • /class/student[1]: select first student element which is child of the class element
   • /class/student[last()] : select last student element which is child of the class element.
   • /class/student[@rollno = 493] : select student element with rollno 493
   • /class/student[marks>85] : select student element with marks > 85

2. Expressions

   • double forward slash // : select node in the current document
   • period . : selects the current node
   • double period .. : selects the parent of current node
   • @ : select attributes
   • * : matches any element node

3. Node Types

   • Root
   • Element
   • Text
   • Attribute
   • Comment
   • Processing Instruction
   • Namespace

4. Axes

   • Ancestor
   • Ancestor-or-self
   • Attribute
   • child
   • descendant
   • descendant-or-self
   • Following
   • Following-sibling
   • namespace
   • Preceding
   • parent
   • self