This document provides an overview of XPath axes, functions, and location paths. It defines the different axes like child, parent, and ancestor that can be used to navigate nodes in an XML document. It also lists numerous functions for working with strings, booleans, numbers, and node-sets. Examples are given of location paths to select specific nodes using child axes and predicates. References are included for the XPath 2.0 specification and related recommendations.

4. P P L

5. D:Web TechnologiesXml

7. /
predicate
node test
axis
/child::Contacts/child::Contact[@id=3]/child::phone

8. • child axis • following-sibling axis
• attribute axis • namespace axis
• ancestor axis • parent axis
• ancestor-or-self axis • preceding axis
• descendant axis • preceding-sibling axis
• descedant-or-self axis • self axis
• following axis

9. ancestor-or-self
ancestor
preceding following
parent
preceding-sibling following-sibling
self
child
descendant
descendant-or-seft

10. • //Contact[@id=3]
• //Contact[@title=“Mr”][@age>25]

11. • Boolean boolean(arg) //returns false if object equal to zero/NaN/empty
• Boolean false() //returns the Boolean value false
• Boolean lang(string arg) //to check language which is used in context node
• Boolean not(arg) //
• Boolean true() // returns the Boolean value true

12. • number count(node-set arg) //returns the number of nodes
• node-set id(string arg) //returns a node-set
• last() // returns a value equal to the context size
• string local-name(optional node-set arg) //returns local name(context node)
• string name(optional node-set arg) //returns the nam of node in QName format
• string namespace-uri(optional node-set arg) //returns namespace-uri of node-set
• Number position() //returns value equal to the context position

13. • number ceiling( number arg) //returns the smallest integer greater than this
• number floor(number arg) //returns the largest integer that is lower than this
• number number(arg) //to convert string, Boolean, node-set to number
//returns NaN if can not convert
• number round(number arg) //returns the integer that is closest to the number arg
• number sum(node-set arg) // return sum of node in node-set
// return NaN if node can’t converted to number

14. • string concat(string arg1, arg2) //returns the concatenation of those strings
• Boolean contains(string arg1, arg2) //returns true if arg1 contains arg2
• string normalize-space(string arg1) //=trim & replace whitespace=single space
• Boolean start-with(string arg1, arg2) //returns true if arg1 starts with arg2
• string string(arg) //to convert Boolean, node-set, number to string
• number string-length(string arg) //returns the length of the string arg
• string substring(string arg1, number arg2, optional number arg3) //return substring of arg1
• string substring-before(string arg1, arg2) //
• string substring-after(string arg1, arg2) //
• string translate(string arg1, arg2, arg 3) //

15.  Functions and location paths are orthogonal

16. • /child::Contacts/child::Contact[@id=3]/child::phone
• /Contacts/Contact[@id=3]/phone

17. http://www.w3.org/TR/xpath20/
http://www.w3.org/TR/xpath-functions/
http://www.w3.org/TR/xpath-datamodel/