XPath functions

The following is an annotated list of core XPath functions and XSLT-specific additions to XPath, including a description, syntax, a list of arguments, result-type, source in the appropriate W3C Recommendation. For further information on using XPath/XSLT functions, please see the For Further Reading page.

boolean: The boolean function evaluates an expression and returns true or false.
ceiling: The ceiling function evaluates a decimal number and returns the smallest integer greater than or equal to the decimal number.
choose: The choose function returns one of the specified objects based on a boolean parameter.
concat: The concat function concatenates two or more strings and returns the resulting string.
contains: The contains function determines whether the first argument string contains the second argument string and returns boolean true or false.
count: The count function counts the number of nodes in a node-set and returns an integer.
current: The current function can be used to get the context node in an XSLT instruction.
document: The document finds a node-set in an external document, or multiple external documents, and returns the resulting node-set.
element-available: The element-available function determines if an element is available and returns true or false.
false: The false function returns boolean false.
floor: The floor function evaluates a decimal number and returns the largest integer less than or equal to the decimal number.
format-number: The format-number function evaluates a number and returns a string representing the number in a given format.
function-available: The function-available function determines if a given function is available and returns boolean true or false.
generate-id: The generate-id function generates a unique id for the first node in a given node-set and returns a string containing that id.
id: The id function finds nodes matching the given ids and returns a node-set containing the identified nodes.
key: The key function returns a node-set of nodes that have the given value for the given key.
lang: The lang function determines whether the context node matches the given language and returns boolean true or false.
last: The last function returns a number equal to the context size from the expression evaluation context.
local-name: The local-name function returns a string representing the local name of the first node in a given node-set.
name: The name function returns a string representing the QName of the first node in a given node-set.
namespace-uri: The namespace-uri function returns a string representing the namespace URI of the first node in a given node-set.
normalize-space: The normalize-space function strips leading and trailing white-space from a string, replaces sequences of whitespace characters by a single space, and returns the resulting string.
not: The not function evaluates a boolean expression and returns the opposite value.
number: The number function converts an object to a number and returns the number.
position: The position function returns a number equal to the context position from the expression evaluation context.
round: The round function returns a number that is the nearest integer to the given number.
starts-with: The starts-with checks whether the first string starts with the second string and returns true or false.
string: The string function converts the given argument to a string.
string-length: The string-length function returns a number equal to the number of characters in a given string.
substring: The substring function returns a part of a given string.
substring-after: The substring-after function returns a string that is the rest of a given string after a given substring.
substring-before: The substring-before function returns a string that is the part of a given string before a given substring.
sum: The sum function returns a number that is the sum of the numeric values of each node in a given node-set.
system-property: The system-property function returns an object representing the given system-property.
translate: The translate function evaluates a string and a set of characters to translate and returns the translated string.
true: The true function returns a boolean value of true.
unparsed-entity-url: The unparsed-entity-url() function returns the URI of the unparsed entity with the given name. This is non-XML data referenced in the DTD of the source document.