Funzioni XSLT, XPath e XQuery
XSLT 2.0, XPath 2.0 e XQuery 1.0 condividono la stessa libreria di funzioni.
Riferimento alle funzioni
Il prefisso predefinito per lo spazio dei nomi della funzione è fn:
L'URI dello spazio dei nomi della funzione è: http://www.w3.org/2005/xpath-functions
Suggerimento: le funzioni vengono spesso chiamate con il prefisso fn:, ad esempio fn:string(). Tuttavia, poiché fn: è il prefisso predefinito dello spazio dei nomi, non è necessario che i nomi delle funzioni abbiano un prefisso quando vengono chiamati.
Funzioni di accesso
| 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 |
Funzioni di errore e traccia
| 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 |
Funzioni sui valori numerici
| 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') |
| fn:abs(num) | Returns the absolute value of the argument
Example: abs(3.14) Example: abs(-3.14) |
| fn:ceiling(num) | Returns the smallest integer that is greater than the number argument
Example: ceiling(3.14) |
| fn:floor(num) | Returns the largest integer that is not greater than the number argument
Example: floor(3.14) |
| fn:round(num) | Rounds the number argument to the nearest integer
Example: round(3.14) |
| fn:round-half-to-even() | Example: round-half-to-even(0.5) Result: 0 Example: round-half-to-even(1.5) Example: round-half-to-even(2.5) |
Funzioni sulle stringhe
| 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) |
| 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)) |
| fn:string-to-codepoints(string) | Returns the sequence of the Unicode standard code points from a string
Example: string-to-codepoints("Thérèse") |
| 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') |
| fn:concat(string,string,...) | Returns the concatenation of the strings
Example: concat('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!'), ' ') Example: string-join(('We', 'are', 'having', 'fun!')) Example:string-join((), 'sep') |
| 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) Example: substring('Beatles',2) |
| 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') |
| 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 ') |
| fn:normalize-unicode() | |
| fn:upper-case(string) | Converts the string argument to upper-case
Example: upper-case('The XML') |
| fn:lower-case(string) | Converts the string argument to lower-case
Example: lower-case('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') Example: translate('12:30','03','54') Example: translate('12:30','0123','abcd') |
| 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()) Example: escape-uri ("http://example.com/~bébé", false()) |
| fn:contains(string1,string2) | Returns true if string1 contains string2, otherwise it returns false
Example: contains('XML','XM') |
| fn:starts-with(string1,string2) | Returns true if string1 starts with string2, otherwise it returns false
Example: starts-with('XML','X') |
| fn:ends-with(string1,string2) | Returns true if string1 ends with string2, otherwise it returns false
Example: ends-with('XML','X') |
| fn:substring-before(string1,string2) | Returns the start of string1 before string2 occurs in it
Example: substring-before('12/10','/') |
| fn:substring-after(string1,string2) | Returns the remainder of string1 after string2 occurs in it
Example: substring-after('12/10','/') |
| fn:matches(string,pattern) | Returns true if the string argument matches the pattern, otherwise, it returns false
Example: matches("Merano", "ran") |
| 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", "*") Example: replace("Bella Italia", "l", "") |
| fn:tokenize(string,pattern) | Example: tokenize("XPath is fun", "\s+") Result: ("XPath", "is", "fun") |
Funzioni per anyURI
| Name | Description |
|---|---|
| fn:resolve-uri(relative,base) |
Funzioni sui valori booleani
| 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()) |
| fn:true() | Returns the boolean value true
Example: true() |
| fn:false() | Returns the boolean value false
Example: false() |
Funzioni su Durate, Date e Orari
Funzioni di estrazione dei componenti su durate, date e orari
| 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")) |
| 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")) |
| 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")) |
| 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")) |
| 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")) |
| 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")) |
| 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")) |
| 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")) |
| 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")) |
| 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")) |
| 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")) |
| 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")) |
| 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 |
Funzioni relative ai 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() |
Funzioni sui nodi
| 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 Example: Lang("de") is false for |
| 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 |
Funzioni sulle sequenze
Funzioni generali sulle sequenze
| 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) Example: index-of (("a", "dog", "and", "a", "duck"), "a") Example: index-of ((15, 40, 25, 40, 10), 18) |
| 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) Example: remove(("ab", "cd", "ef"), 1) Example: remove(("ab", "cd", "ef"), 4) |
| 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)) |
| 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)) |
| fn:distinct-values((item,item,...),collation) | Returns only distinct (different) values
Example: distinct-values((1, 2, 3, 1, 2)) |
| 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") Example: insert-before(("ab", "cd"), 1, "gh") Example: insert-before(("ab", "cd"), 2, "gh") Example: insert-before(("ab", "cd"), 5, "gh") |
| fn:reverse((item,item,...)) | Returns the reversed order of the items specified
Example: reverse(("ab", "cd", "ef")) Example: reverse(("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, $item3,...), 3) Example: subsequence(($item1, $item2, $item3, ...), 2, 2) |
| fn:unordered((item,item,...)) | Returns the items in an implementation dependent order |
Funzioni che verificano la cardinalità delle sequenze
| 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 |
Uguale, Unione, Intersezione ed Eccetto
| Name | Description |
|---|---|
| fn:deep-equal(param1,param2,collation) | Returns true if param1 and param2 are deep-equal to each other, otherwise it returns false |
Funzioni aggregate
| 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)) |
| fn:max((arg,arg,...)) | Returns the argument that is greater than the others
Example: max((1,2,3)) Example: max(('a', 'k')) |
| fn:min((arg,arg,...)) | Returns the argument that is less than the others
Example: min((1,2,3)) Example: min(('a', 'k')) |
| fn:sum(arg,arg,...) | Returns the sum of the numeric value of each node in the specified node-set |
Funzioni che generano sequenze
| 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) |
Funzioni di contesto
| Name | Description |
|---|---|
| fn:position() | Returns the index position of the node that is currently being processed
Example: //book[position()<=3] |
| fn:last() | Returns the number of items in the processed node list
Example: //book[last()] |
| 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 |
Funzioni XSLT
Inoltre, ci sono le seguenti funzioni XSLT integrate:
| 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 |