String Module

Updated with Version 10: Renamed from Strings Module to String Module. The namespace URI has been updated as well.

This XQuery Module contains functions for string operations and computations.

Conventions

All functions and errors in this module and errors are assigned to the http://basex.org/modules/string namespace, which is statically bound to the string prefix.

Computations

string:levenshtein

Signature	string:levenshtein( $string1 as xs:string, $string2 as xs:string ) as xs:double
Summary	Computes the Damerau-Levenshtein Distance for two strings and returns a double value (0.0 - 1.0). The returned value is computed as follows: 1.0 – distance / max(length of strings) 1.0 is returned if the strings are equal; 0.0 is returned if the strings are too different.
Examples	string:levenshtein("flower", "flower") returns 1 string:levenshtein("flower", "lewes") returns 0.5 In the following query, the input is first normalized (words are stemmed, converted to lower case, and diacritics are removed). It returns 1: <syntaxhighlight lang="xquery"> let $norm := ft:normalize(?, map { 'stemming': true() }) return string:levenshtein($norm("HOUSES"), $norm("house")) </syntaxhighlight>

string:soundex

Signature	string:soundex( $string as xs:string ) as xs:string
Summary	Computes the Soundex value for the specified string. The algorithm can be used to find and index English words with similar pronouncation.
Examples	string:soundex("Michael") returns M240 string:soundex("OBrien") = string:soundex("O'Brien") returns true

string:cologne-phonetic

Signature	string:cologne-phonetic( $string as xs:string ) as xs:string
Summary	Computes the Kölner Phonetik value for the specified string. Similar to Soundex, the algorithm is used to find similarly pronounced words, but for the German language. As the first returned digit can be 0, the value is returned as string.
Examples	string:cologne-phonetic("Michael") returns 645 every $s in ("Mayr", "Maier", "Meier") satisfies string:cologne-phonetic($s) = "67" returns true

Formatting

The functions in this section have been adopted from the obsolete Output Module.

string:format

Signature	string:format( $format as xs:string, $inputs as item() (: ... :) ) as xs:string
Summary	Returns a formatted string. The remaining $input are inserted to the $format string, according to Java’s printf syntax.
Errors	format: The specified format is not valid.
Examples	string:format("%b", true()) returns true. string:format("%06d", 256) returns 000256. string:format("%e", 1234.5678) returns 1.234568e+03.

string:cr

Signature	string:cr() as xs:string
Summary	Returns a single carriage return character (
).

string:nl

Signature	string:nl() as xs:string
Summary	Returns a single newline character (
).

string:tab

Signature	string:tab() as xs:string
Summary	Returns a single tabulator character (	).

Changelog

Version 10.0

• Updated: Renamed from Strings Module to String Module. The namespace URI has been updated as well.
• Updated: string:format, string:cr, string:nl and string:tab adopted from the obsolete Output Module.

The Module was introduced with Version 8.3. Functions were adopted from the obsolete Utility and Output Modules.