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XSLT, XPath, and XQuery Functions


XSLT 2.0, XPath 2.0, and XQuery 1.0, share the same functions library.


Functions 参考

The default prefix for the function namespace is fn:
The URI of the function namespace is: http://www.w3.org/2005/xpath-functions

Tip: Functions are often called with the fn: prefix, such as fn:string(). However, since fn: is the default prefix of the namespace, the function names do not need to be prefixed when called.

Accessor Functions

Name Description
fn:node-name(node) Returns the node-name of the argument node
fn:nilled(node) Returns a Boolean value indicating whether the argument node is nilled
fn:data(item.item,...) Takes a sequence of items and returns a sequence of atomic values
fn:base-uri()
fn:base-uri(node)
Returns the value of the base-uri property of the current or specified node
fn:document-uri(node) Returns the value of the document-uri property for the specified node

Error and Trace Functions

Name Description
fn:error()
fn:error(error)
fn:error(error,description)
fn:error(error,description,error-object)
Example: error(fn:QName('http://example.com/test', 'err:toohigh'), 'Error: Price is too high')

Result: Returns http://example.com/test#toohigh and the string "Error: Price is too high" to the external processing environment

fn:trace(value,label) Used to debug queries


Functions on Numeric Values

Name Description
fn:number(arg) Returns the numeric value of the argument. The argument could be a boolean, string, or node-set

Example: number('100')
Result: 100

fn:abs(num) Returns the absolute value of the argument

Example: abs(3.14)
Result: 3.14

Example: abs(-3.14)
Result: 3.14

fn:ceiling(num) Returns the smallest integer that is greater than the number argument

Example: ceiling(3.14)
Result: 4

fn:floor(num) Returns the largest integer that is not greater than the number argument

Example: floor(3.14)
Result: 3

fn:round(num) Rounds the number argument to the nearest integer

Example: round(3.14)
Result: 3

fn:round-half-to-even() Example: round-half-to-even(0.5)
Result: 0

Example: round-half-to-even(1.5)
Result: 2

Example: round-half-to-even(2.5)
Result: 2

Functions on Strings

Name Description
fn:string(arg) Returns the string value of the argument. The argument could be a number, boolean, or node-set

Example: string(314)
Result: "314"

fn:codepoints-to-string((int,int,...)) Creates a string from a sequence of the Unicode Standard code points

Example: codepoints-to-string((84, 104, 233, 114, 232, 115, 101))
Result: 'Thérèse'

fn:string-to-codepoints(string) Returns the sequence of the Unicode standard code points from a string

Example: string-to-codepoints("Thérèse")
Result: (84, 104, 233, 114, 232, 115, 101)

fn:codepoint-equal(comp1,comp2) Returns true if the value of comp1 is equal to the value of comp2, according to the Unicode code point collation (http://www.w3.org/2005/02/xpath-functions/collation/codepoint), otherwise it returns false
fn:compare(comp1,comp2)
fn:compare(comp1,comp2,collation)
Returns -1 if comp1 is less than comp2, 0 if comp1 is equal to comp2, or 1 if comp1 is greater than comp2 (according to the rules of the collation that is used)

Example: compare('ghi', 'ghi')
Result: 0

fn:concat(string,string,...) Returns the concatenation of the strings

Example: concat('XPath ','is ','FUN!')
Result: 'XPath is FUN!'

fn:string-join((string,string,...),sep) Returns a string created by concatenating the string arguments and using the sep argument as the separator

Example: string-join(('We', 'are', 'having', 'fun!'), ' ')
Result: ' We are having fun! '

Example: string-join(('We', 'are', 'having', 'fun!'))
Result: 'Wearehavingfun!'

Example:string-join((), 'sep')
Result: ''

fn:substring(string,start,len)
fn:substring(string,start)
Returns the substring from the start position to the specified length. Index of the first character is 1. If length is omitted it returns the substring from the start position to the end

Example: substring('Beatles',1,4)
Result: 'Beat'

Example: substring('Beatles',2)
Result: 'eatles'

fn:string-length(string)
fn:string-length()
Returns the length of the specified string. If there is no string argument it returns the length of the string value of the current node

Example: string-length('Beatles')
Result: 7

fn:normalize-space(string)
fn:normalize-space()
Removes leading and trailing spaces from the specified string, and replaces all internal sequences of white space with one and returns the result. If there is no string argument it does the same on the current node

Example: normalize-space(' The   XML ')
Result: 'The XML'

fn:normalize-unicode()  
fn:upper-case(string) Converts the string argument to upper-case

Example: upper-case('The XML')
Result: 'THE XML'

fn:lower-case(string) Converts the string argument to lower-case

Example: lower-case('The XML')
Result: 'the xml'

fn:translate(string1,string2,string3) Converts string1 by replacing the characters in string2 with the characters in string3

Example: translate('12:30','30','45')
Result: '12:45'

Example: translate('12:30','03','54')
Result: '12:45'

Example: translate('12:30','0123','abcd')
Result: 'bc:da'

fn:escape-uri(stringURI,esc-res) Example: escape-uri("http://example.com/test#car", true())
Result: "http%3A%2F%2Fexample.com%2Ftest#car"

Example: escape-uri("http://example.com/test#car", false())
Result: "http://example.com/test#car"

Example: escape-uri ("http://example.com/~bébé", false())
Result: "http://example.com/~b%C3%A9b%C3%A9"

fn:contains(string1,string2) Returns true if string1 contains string2, otherwise it returns false

Example: contains('XML','XM')
Result: true

fn:starts-with(string1,string2) Returns true if string1 starts with string2, otherwise it returns false

Example: starts-with('XML','X')
Result: true

fn:ends-with(string1,string2) Returns true if string1 ends with string2, otherwise it returns false

Example: ends-with('XML','X')
Result: false

fn:substring-before(string1,string2) Returns the start of string1 before string2 occurs in it

Example: substring-before('12/10','/')
Result: '12'

fn:substring-after(string1,string2) Returns the remainder of string1 after string2 occurs in it

Example: substring-after('12/10','/')
Result: '10'

fn:matches(string,pattern) Returns true if the string argument matches the pattern, otherwise, it returns false

Example: matches("Merano", "ran")
Result: true

fn:replace(string,pattern,replace) Returns a string that is created by replacing the given pattern with the replace argument

Example: replace("Bella Italia", "l", "*")
Result: 'Be**a Ita*ia'

Example: replace("Bella Italia", "l", "")
Result: 'Bea Itaia'

fn:tokenize(string,pattern) Example: tokenize("XPath is fun", "\s+")
Result: ("XPath", "is", "fun")

Functions for anyURI

Name Description
fn:resolve-uri(relative,base)  

Functions on Boolean Values

Name Description
fn:boolean(arg) Returns a boolean value for a number, string, or node-set
fn:not(arg) The argument is first reduced to a boolean value by applying the boolean() function. Returns true if the boolean value is false, and false if the boolean value is true

Example: not(true())
Result: false

fn:true() Returns the boolean value true

Example: true()
Result: true

fn:false() Returns the boolean value false

Example: false()
Result: false

Functions on Durations, Dates and Times

Component Extraction Functions on Durations, Dates and Times

Name Description
fn:dateTime(date,time) Converts the arguments to a date and a time
fn:years-from-duration(datetimedur) Returns an integer that represents the years component in the canonical lexical representation of the value of the argument
fn:months-from-duration(datetimedur) Returns an integer that represents the months component in the canonical lexical representation of the value of the argument
fn:days-from-duration(datetimedur) Returns an integer that represents the days component in the canonical lexical representation of the value of the argument
fn:hours-from-duration(datetimedur) Returns an integer that represents the hours component in the canonical lexical representation of the value of the argument
fn:minutes-from-duration(datetimedur) Returns an integer that represents the minutes component in the canonical lexical representation of the value of the argument
fn:seconds-from-duration(datetimedur) Returns a decimal that represents the seconds component in the canonical lexical representation of the value of the argument
fn:year-from-dateTime(datetime) Returns an integer that represents the year component in the localized value of the argument

Example: year-from-dateTime(xs:dateTime("2005-01-10T12:30-04:10"))
Result: 2005

fn:month-from-dateTime(datetime) Returns an integer that represents the month component in the localized value of the argument

Example: month-from-dateTime(xs:dateTime("2005-01-10T12:30-04:10"))
Result: 01

fn:day-from-dateTime(datetime) Returns an integer that represents the day component in the localized value of the argument

Example: day-from-dateTime(xs:dateTime("2005-01-10T12:30-04:10"))
Result: 10

fn:hours-from-dateTime(datetime) Returns an integer that represents the hours component in the localized value of the argument

Example: hours-from-dateTime(xs:dateTime("2005-01-10T12:30-04:10"))
Result: 12

fn:minutes-from-dateTime(datetime) Returns an integer that represents the minutes component in the localized value of the argument

Example: minutes-from-dateTime(xs:dateTime("2005-01-10T12:30-04:10"))
Result: 30

fn:seconds-from-dateTime(datetime) Returns a decimal that represents the seconds component in the localized value of the argument

Example: seconds-from-dateTime(xs:dateTime("2005-01-10T12:30:00-04:10"))
Result: 0

fn:timezone-from-dateTime(datetime) Returns the time zone component of the argument if any
fn:year-from-date(date) Returns an integer that represents the year in the localized value of the argument

Example: year-from-date(xs:date("2005-04-23"))
Result: 2005

fn:month-from-date(date) Returns an integer that represents the month in the localized value of the argument

Example: month-from-date(xs:date("2005-04-23"))
Result: 4

fn:day-from-date(date) Returns an integer that represents the day in the localized value of the argument

Example: day-from-date(xs:date("2005-04-23"))
Result: 23

fn:timezone-from-date(date) Returns the time zone component of the argument if any
fn:hours-from-time(time) Returns an integer that represents the hours component in the localized value of the argument

Example: hours-from-time(xs:time("10:22:00"))
Result: 10

fn:minutes-from-time(time) Returns an integer that represents the minutes component in the localized value of the argument

Example: minutes-from-time(xs:time("10:22:00"))
Result: 22

fn:seconds-from-time(time) Returns an integer that represents the seconds component in the localized value of the argument

Example: seconds-from-time(xs:time("10:22:00"))
Result: 0

fn:timezone-from-time(time) Returns the time zone component of the argument if any
fn:adjust-dateTime-to-timezone(datetime,timezone) If the timezone argument is empty, it returns a dateTime without a timezone. Otherwise, it returns a dateTime with a timezone
fn:adjust-date-to-timezone(date,timezone) If the timezone argument is empty, it returns a date without a timezone. Otherwise, it returns a date with a timezone
fn:adjust-time-to-timezone(time,timezone) If the timezone argument is empty, it returns a time without a timezone. Otherwise, it returns a time with a timezone

Functions Related to QNames

Name Description
fn:QName()  
fn:local-name-from-QName()  
fn:namespace-uri-from-QName()  
fn:namespace-uri-for-prefix()  
fn:in-scope-prefixes()  
fn:resolve-QName()  

Functions on Nodes

Name Description
fn:name()
fn:name(nodeset)
Returns the name of the current node or the first node in the specified node set
fn:local-name()
fn:local-name(nodeset)
Returns the name of the current node or the first node in the specified node set - without the namespace prefix
fn:namespace-uri()
fn:namespace-uri(nodeset)
Returns the namespace URI of the current node or the first node in the specified node set
fn:lang(lang) Returns true if the language of the current node matches the language of the specified language

Example: Lang("en") is true for
<p xml:lang="en">...</p>

Example: Lang("de") is false for
<p xml:lang="en">...</p>

fn:root()
fn:root(node)
Returns the root of the tree to which the current node or the specified belongs. This will usually be a document node

Functions on Sequences

General Functions on Sequences

Name Description
fn:index-of((item,item,...),searchitem) Returns the positions within the sequence of items that are equal to the searchitem argument

Example: index-of ((15, 40, 25, 40, 10), 40)
Result: (2, 4)

Example: index-of (("a", "dog", "and", "a", "duck"), "a")
Result (1, 4)

Example: index-of ((15, 40, 25, 40, 10), 18)
Result: ()

fn:remove((item,item,...),position) Returns a new sequence constructed from the value of the item arguments - with the item specified by the position argument removed

Example: remove(("ab", "cd", "ef"), 0)
Result: ("ab", "cd", "ef")

Example: remove(("ab", "cd", "ef"), 1)
Result: ("cd", "ef")

Example: remove(("ab", "cd", "ef"), 4)
Result: ("ab", "cd", "ef")

fn:empty(item,item,...) Returns true if the value of the arguments IS an empty sequence, otherwise it returns false

Example: empty(remove(("ab", "cd"), 1))
Result: false

fn:exists(item,item,...) Returns true if the value of the arguments IS NOT an empty sequence, otherwise it returns false

Example: exists(remove(("ab"), 1))
Result: false

fn:distinct-values((item,item,...),collation) Returns only distinct (different) values

Example: distinct-values((1, 2, 3, 1, 2))
Result: (1, 2, 3)

fn:insert-before((item,item,...),pos,inserts) Returns a new sequence constructed from the value of the item arguments - with the value of the inserts argument inserted in the position specified by the pos argument

Example: insert-before(("ab", "cd"), 0, "gh")
Result: ("gh", "ab", "cd")

Example: insert-before(("ab", "cd"), 1, "gh")
Result: ("gh", "ab", "cd")

Example: insert-before(("ab", "cd"), 2, "gh")
Result: ("ab", "gh", "cd")

Example: insert-before(("ab", "cd"), 5, "gh")
Result: ("ab", "cd", "gh")

fn:reverse((item,item,...)) Returns the reversed order of the items specified

Example: reverse(("ab", "cd", "ef"))
Result: ("ef", "cd", "ab")

Example: reverse(("ab"))
Result: ("ab")

fn:subsequence((item,item,...),start,len) Returns a sequence of items from the position specified by the start argument and continuing for the number of items specified by the len argument. The first item is located at position 1

Example: subsequence(($item1, $item2, $item3,...), 3)
Result: ($item3, ...)

Example: subsequence(($item1, $item2, $item3, ...), 2, 2)
Result: ($item2, $item3)

fn:unordered((item,item,...)) Returns the items in an implementation dependent order

Functions That Test the Cardinality of Sequences

Name Description
fn:zero-or-one(item,item,...) Returns the argument if it contains zero or one items, otherwise it raises an error
fn:one-or-more(item,item,...) Returns the argument if it contains one or more items, otherwise it raises an error
fn:exactly-one(item,item,...) Returns the argument if it contains exactly one item, otherwise it raises an error

Equals, Union, Intersection and Except

Name Description
fn:deep-equal(param1,param2,collation) Returns true if param1 and param2 are deep-equal to each other, otherwise it returns false

Aggregate Functions

Name Description
fn:count((item,item,...)) Returns the count of nodes
fn:avg((arg,arg,...)) Returns the average of the argument values

Example: avg((1,2,3))
Result: 2

fn:max((arg,arg,...)) Returns the argument that is greater than the others

Example: max((1,2,3))
Result: 3

Example: max(('a', 'k'))
Result: 'k'

fn:min((arg,arg,...)) Returns the argument that is less than the others

Example: min((1,2,3))
Result: 1

Example: min(('a', 'k'))
Result: 'a'

fn:sum(arg,arg,...) Returns the sum of the numeric value of each node in the specified node-set

Functions that Generate Sequences

Name Description
fn:id((string,string,...),node) Returns a sequence of element nodes that have an ID value equal to the value of one or more of the values specified in the string argument
fn:idref((string,string,...),node) Returns a sequence of element or attribute nodes that have an IDREF value equal to the value of one or more of the values specified in the string argument
fn:doc(URI)  
fn:doc-available(URI) Returns true if the doc() function returns a document node, otherwise it returns false
fn:collection()
fn:collection(string)
 

Context Functions

Name Description
fn:position() Returns the index position of the node that is currently being processed

Example: //book[position()<=3]
Result: Selects the first three book elements

fn:last() Returns the number of items in the processed node list

Example: //book[last()]
Result: Selects the last book element

fn:current-dateTime() Returns the current dateTime (with timezone)
fn:current-date() Returns the current date (with timezone)
fn:current-time() Returns the current time (with timezone)
fn:implicit-timezone() Returns the value of the implicit timezone
fn:default-collation() Returns the value of the default collation
fn:static-base-uri() Returns the value of the base-uri

XSLT Functions

In addition, there are the following built-in XSLT functions:

Name Description
current() Returns the current node
document() Used to access the nodes in an external XML document
element-available() Tests whether the element specified is supported by the XSLT processor
format-number() Converts a number into a string
function-available() Tests whether the function specified is supported by the XSLT processor
generate-id() Returns a string value that uniquely identifies a specified node
key() Returns a node-set using the index specified by an <xsl:key> element
system-property() Returns the value of the system properties
unparsed-entity-uri() Returns the URI of an unparsed entity




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