XPath

Xpath content

XPath - Some Important Abbreviations

Submitted by admin on Mon, 01/31/2011 - 13:24

XPath

The most important abbreviation is thatchild::can be omitted from a location step. In effect,child is the default axis.

For example, a location path

Data/username is short for

child::Data/child::username

There is also an abbreviation for attributes: attribute::can be abbreviated to @.

For example, a location path

/*/*/*/*/*/*/*/perm[@type="admin"]is short for

/*/*/*/*/*/*/*/child::perm[attribute::type="admin"]

... and so selects

permchildren with a type attribute with value equal to admin.

//is short for /descendant-or-self::node()/.

For example,

1.)

//perm is short for

/descendant-or-self::node()/child::perm

... and so will select anyperm element in the document (even a perm element that is a document element will be selected by //perm since the document element node is a child of the root node);

2.)

Data//perm is short for

Data/descendant-or-self::node()/child::perm

... and so will select all perm descendants of Data children.

A location step of .. is short for parent::node().

For example,

../title is short for

parent::node()/child::title

... and so will select the title children of the parent of the context node

Example that can be tested on example XML_example.xml:

//getUserToken/usertoken/permissions/../usernameis short for

//getUserToken/usertoken/permissions/parent::node()/child::username

XPath - Abbreviated Syntax

Submitted by admin on Mon, 01/31/2011 - 07:47

XPath

XPath	Description
*	selects all element children of the context node (child::*)
text()	selects all text node children of the context node
@name	selects the `name` attribute of the context node (attribute::name)
@*	selects all the attributes of the context node (attribute::*)
perm[1]	selects the first `perm` child of the context node
perm[last()]	selects the last `perm` child of the context node
../perm	select the `perm` children of the parent of the context node (parent::name)
perm	selects the `perm` element, child of the context node (child::perm)
//perm	selects all the `perm)` descendants of the document root and thus selects all `perm` elements in the same document as the context node (descendant::perm
.	selects the context node (self::node())
..	selects the parent of the context node (parent::node())
//permissions/perm[5]	selects the fifth `perm` of the `permissions`
../@attName	selects the `attName` attribute of the parent of the context node
`perm[@type="admin"]`	selects all `perm` children of the context node that have a `type` attribute with value `admin`
`para[@type="admin"][5]`	selects the fifth `perm` child of the context node that has a `type` attribute with value `admin`
`para[5][@type="admin"]`	selects the fifth `perm` child of the context node if that child has a `type` attribute with value `admin`

XPath - String, Boolean and Number Functions

Submitted by admin on Mon, 01/31/2011 - 07:29

XPath

String functions	Boolean functions	Number functions
string string(object?) converts an object to a string	boolean not(boolean) returns true if its argument is false, and false otherwise	number number(object?) converts its argument to a number
string concat(string, string, string*) returns the concatenation of its arguments	boolean true() returns true	number sum(node-set) returns the sum, for each node in the argument node-set
boolean starts-with(string, string) returns true if the first argument string starts with the second argument string, and otherwise returns false	boolean false() returns false	number floor(number) returns the largest (closest to positive infinity) number that is not greater than the argument and that is an integer
boolean contains(string, string) returns true if the first argument string contains the second argument string, and otherwise returns false	boolean lang(string) returns true or false depending on whether the language of the context node as specified by `xml:lang` attributes is the same as or is a sublanguage of the language specified by the argument string	number ceiling(number) returns the smallest (closest to negative infinity) number that is not less than the argument and that is an integer
string substring-before(string, string) returns the substring of the first argument string that precedes the first occurrence of the second argument string in the first argument string		number round(number) returns the number that is closest to the argument and that is an integer
string substring-after(string, string) returns the substring of the first argument string that follows the first occurrence of the second argument string in the first argument string
string substring(string, number, number?) returns the substring of the first argument starting at the position specified in the second argument with length specified in the third argument
number string-length(string?) returns the number of characters in the string
string normalize-space(string?) returns the argument string with whitespace normalized by stripping leading and trailing whitespace and replacing sequences of whitespace characters by a single space
string translate(string, string, string) returns the first argument string with occurrences of characters in the second argument string replaced by the character at the corresponding position in the third argument string

XPath - Axes and Node Set Functions

Submitted by admin on Mon, 01/31/2011 - 07:26

XPath

Axes	Node Set Functions
`child` axis contains the children of the context node	last() returns a number equal to the context size from the expression evaluation context
`descendant` axis contains the descendants of the context node; a descendant is a child or a child of a child and so on	position() function returns a number equal to the context position from the expression evaluation context
`parent` axis contains the parent of the context node	count(node-set) returns the number of nodes in the argument node-set
`ancestor` axis contains the ancestors of the context node; the ancestors of the context node consist of the parent of context node and the parent's parent and so on	node-set id(object) selects elements by their unique ID
`following-sibling` axis contains all the following siblings of the context node	string local-name(node-set?) returns the local part of the expanded-name of the node in the argument node-set that is first in document order
`preceding-sibling` axis contains all the preceding siblings of the context node	string namespace-uri(node-set?) returns the namespace URI of the expanded-name of the node in the argument node-set that is first indocument order
`following` axis contains all nodes in the same document as the context node that are after the context node in document order, excluding any descendants and excluding attribute nodes and namespace nodes	string name(node-set?) returns a string containing a QName representing the expanded-name of the node in the argument node-set that is first in document order
`preceding` axis contains all nodes in the same document as the context node that are before the context node in document order, excluding any ancestors and excluding attribute nodes and namespace nodes
`attribute` axis contains the attributes of the context node; the axis will be empty unless the context node is an element
`namespace` axis contains the namespace nodes of the context node; the axis will be empty unless the context node is an element
`self` axis contains just the context node itself
`descendant-or-self` axis contains the context node and the descendants of the context node
`ancestor-or-self` axis contains the context node and the ancestors of the context node; thus, the ancestor axis will always include the root node

XPath - Functions (all)

Submitted by admin on Mon, 01/31/2011 - 07:20

XPath

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

XPath includes many built-in functions. There are functions for string values, numeric values, date and time comparison, node and QName manipulation, sequence manipulation, Boolean values, and more.

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

Before Xpath examples, there must be a part of theory and probably a table with path locations axes and functions (number, string, boolean) as a resume after theory!

Note: This document describes Xpath version 1.0 that is implemented in Sterling Integrator.

All the Xpath functions:

Axes	Node Set Functions	String functions	Boolean functions	Number functions
`Child` axis contains the children of the context node	last() returns a number equal to the context size from the expression evaluation context	string string(object?) converts an object to a string	boolean boolean(object) converts its argument to a boolean	number number(object?) converts its argument to a number
`descendant` axis contains the descendants of the context node; a descendant is a child or a child of a child and so on	position() function returns a number equal to the context position from the expression evaluation context	string concat(string, string, string*) returns the concatenation of its arguments	boolean not(boolean) returns true if its argument is false, and false otherwise	number sum(node-set) returns the sum, for each node in the argument node-set
`parent` axis contains the parent of the context node	count(node-set) returns the number of nodes in the argument node-set	boolean starts-with(string, string) returns true if the first argument string starts with the second argument string, and otherwise returns false	boolean true() returns true	number floor(number) returns the largest (closest to positive infinity) number that is not greater than the argument and that is an integer
`ancestor` axis contains the ancestors of the context node; the ancestors of the context node consist of the parent of context node and the parent's parent and so on	node-set id(object) selects elements by their unique ID	boolean contains(string, string) returns true if the first argument string contains the second argument string, and otherwise returns false	boolean false() returns false	number ceiling(number) returns the smallest (closest to negative infinity) number that is not less than the argument and that is an integer
`following-sibling` axis contains all the following siblings of the context node	string *local-name(node-set?)* returns the local part of the expanded-name of the node in the argument node-set that is first in document order	string substring-before(string, string) returns the substring of the first argument string that precedes the first occurrence of the second argument string in the first argument string	boolean lang(string) returns true or false depending on whether the language of the context node as specified by `xml:lang` attributes is the same as or is a sublanguage of the language specified by the argument string	number round(number) returns the number that is closest to the argument and that is an integer
`preceding-sibling` axis contains all the preceding siblings of the context node	string namespace-uri(node-set?) returns the namespace URI of the expanded-name of the node in the argument node-set that is first indocument order	string substring-after(string, string) returns the substring of the first argument string that follows the first occurrence of the second argument string in the first argument string
`following` axis contains all nodes in the same document as the context node that are after the context node in document order, excluding any descendants and excluding attribute nodes and namespace nodes	string name(node-set?) returns a string containing a QName representing the expanded-name of the node in the argument node-set that is first in document order	string substring(string, number, number?) returns the substring of thefirst argument starting at the position specified in the second argument with length specified in the third argument
`preceding` axis contains all nodes in the same document as the context node that are before the context node in document order, excluding any ancestors and excluding attribute nodes and namespace nodes		number string-length(string?) returns the number of characters in the string
`attribute` axis contains the attributes of the context node; the axis will be empty unless the context node is an element		string normalize-space(string?) returns the argument string with whitespace normalized by stripping leading and trailing whitespace and replacing sequences of whitespace characters by a single space
`namespace` axis contains the namespace nodes of the context node; the axis will be empty unless the context node is an element		string translate(string, string, string) returns the first argument string with occurrences of characters in the second argument string replaced by the character at the corresponding position in the third argument string
`self` axis contains just the context node itself
`descendant-or-self` axis contains the context node and the descendants of the context node
`ancestor-or-self` axis contains the context node and the ancestors of the context node; thus, the ancestor axis will always include the root node

XPath

Submitted by admin on Mon, 01/31/2011 - 07:18

Find the XPath explanation and examples in the following documents.

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World of Integration

XPath

XPath - Some Important Abbreviations

XPath - Abbreviated Syntax

XPath - String, Boolean and Number Functions

XPath - Axes and Node Set Functions

XPath - Functions (all)

XPath

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