Functions on Strings
The functions and operators are defined on the XML Schema Part 2: Datatypes Second Edition xs:string datatype and the datatypes derived from it.
Equality and Comparison of Strings
1. fn:compare
fn:compare($comparand1 as xs:string?,
$comparand2 as xs:string?) as xs:integer?
fn:compare($comparand1 as xs:string?,
$comparand2 as xs:string?,
$collation as xs:string) as xs:integer?
Returns -1, 0, or 1, depending on whether the value of the $comparand1 is respectively less than, equal to, or greater than the value of $comparand2, according to the rules of the collation that is used.
Functions on String Values
1. fn:concat
fn:concat($arg1 as xs:anyAtomicType?,
$arg2 as xs:anyAtomicType?,
... ) as xs:string
Accepts two or more xs:anyAtomicType arguments and casts them to xs:string. Returns the xs:string that is the concatenation of the values of its arguments after conversion.
2. fn:string-join
fn:string-join($arg1 as xs:string*, $arg2 as xs:string) as xs:string
Returns a xs:string created by concatenating the members of the $arg1 sequence using $arg2 as a separator.
3. fn:substring
fn:substring( $sourceString as xs:string?,
$startingLoc as xs:double) as xs:string
fn:substring( $sourceString as xs:string?,
$startingLoc as xs:double,
$length as xs:double) as xs:string
Returns the portion of the value of $sourceString beginning at the position indicated by the value of $startingLoc and continuing for the number of characters indicated by the value of $length. The characters returned do not extend beyond $sourceString. If $startingLoc is zero or negative, only those characters in positions greater than zero are returned.
4. fn:string-length
fn:string-length() as xs:integer fn:string-length($arg as xs:string?) as xs:integer
Returns an xs:integer equal to the length in characters of the value of $arg.
5. fn:upper-case
fn:upper-case($arg as xs:string?) as xs:string
6. fn:lower-case
fn:lower-case($arg as xs:string?) as xs:string
7. fn:encode-for-uri
fn:encode-for-uri($uri-part as xs:string?) as xs:string
This function encodes reserved characters in an xs:string that is intended to be used in the path segment of a URI. It is invertible but not idempotent.
8. fn:iri-to-uri
fn:iri-to-uri($iri as xs:string?) as xs:string
9. fn:escape-html-uri
fn:escape-html-uri($uri as xs:string?) as xs:string
This function escapes all characters except printable characters of the US-ASCII coded character set, specifically the octets ranging from 32 to 126 (decimal). The effect of the function is to escape a URI in the manner html user agents handle attribute values that expect URIs. Each character in $uri to be escaped is replaced by an escape sequence, which is formed by encoding the character as a sequence of octets in UTF-8, and then representing each of these octets in the form %HH, where HH is the hexadecimal representation of the octet. This function must always generate hexadecimal values using the upper-case letters A-F.
Functions Based on Substring Matching
The functions described here examine a string $arg1 to see whether it contains another string $arg2 as a substring. The result depends on whether $arg2 is a substring of $arg1, and if so, on the range of characters in $arg1 which $arg2 matches.
1. fn:contains
fn:contains($arg1 as xs:string?, $arg2 as xs:string?) as xs:boolean
fn:contains( $arg1 as xs:string?,
$arg2 as xs:string?,
$collation as xs:string) as xs:boolean
Returns an xs:boolean indicating whether or not the value of $arg1 contains (at the beginning, at the end, or anywhere within) at least one sequence of collation units that provides a minimal match to the collation units in the value of $arg2, according to the collation that is used. "Minimal match" is defined in Unicode Collation Algorithm.
2. fn:starts-with
fn:starts-with($arg1 as xs:string?, $arg2 as xs:string?) as xs:boolean
fn:starts-with( $arg1 as xs:string?,
$arg2 as xs:string?,
$collation as xs:string) as xs:boolean
Returns an xs:boolean indicating whether or not the value of $arg1 starts with a sequence of collation units that provides a minimal match to the collation units of $arg2 according to the collation that is used. "Minimal match" is defined in Unicode Collation Algorithm.
3. fn:ends-with
fn:ends-with($arg1 as xs:string?, $arg2 as xs:string?) as xs:boolean
fn:ends-with( $arg1 as xs:string?,
$arg2 as xs:string?,
$collation as xs:string) as xs:boolean
4. fn:substring-before
fn:substring-before($arg1 as xs:string?, $arg2 as xs:string?) as xs:string
fn:substring-before( $arg1 as xs:string?,
$arg2 as xs:string?,
$collation as xs:string) as xs:string
Returns the substring of the value of $arg1 that precedes in the value of $arg1 the first occurrence of a sequence of collation units that provides a minimal match to the collation units of $arg2 according to the collation that is used.
5. fn:substring-after
fn:substring-after($arg1 as xs:string?, $arg2 as xs:string?) as xs:string
fn:substring-after( $arg1 as xs:string?,
$arg2 as xs:string?,
$collation as xs:string) as xs:string
String Functions that Use Pattern Matching
The three functions described here make use of a regular expression syntax for pattern matching. The regular expression syntax is described here.
1. fn:matches
fn:matches($input as xs:string?, $pattern as xs:string) as xs:boolean
fn:matches( $input as xs:string?,
$pattern as xs:string,
$flags as xs:string) as xs:boolean
The function returns true if $input matches the regular expression supplied as $pattern as influenced by the value of $flags, if present; otherwise, it returns false.
The effect of calling the first version of this function (omitting the argument $flags) is the same as the effect of calling the second version with the $flags argument set to a zero-length string. Flags are defined in 7.6.1.1 Flags.
2. fn:replace
fn:replace( $input as xs:string?,
$pattern as xs:string,
$replacement as xs:string) as xs:string
fn:replace( $input as xs:string?,
$pattern as xs:string,
$replacement as xs:string,
$flags as xs:string) as xs:string
The function returns the xs:string that is obtained by replacing each non-overlapping substring of $input that matches the given $pattern with an occurrence of the $replacement string.
3. fn:tokenize
fn:tokenize($input as xs:string?, $pattern as xs:string) as xs:string*
fn:tokenize( $input as xs:string?,
$pattern as xs:string,
$flags as xs:string) as xs:string*
This function breaks the $input string into a sequence of strings, treating any substring that matches $pattern as a separator. The separators themselves are not returned.