Difference between revisions of "String Module"
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=Conventions= | =Conventions= | ||
− | All functions in this module and errors are assigned to the <code><nowiki>http://basex.org/modules/strings</nowiki></code> namespace, which is statically bound to the {{Code|strings}} prefix.<br/> | + | All functions and errors in this module and errors are assigned to the <code><nowiki>http://basex.org/modules/strings</nowiki></code> namespace, which is statically bound to the {{Code|strings}} prefix.<br/> |
=Functions= | =Functions= | ||
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|- | |- | ||
| '''Summary''' | | '''Summary''' | ||
− | |Computes the [https://en.wikipedia.org/wiki/Damerau%E2%80%93Levenshtein_distance Damerau-Levenshtein Distance] for two strings and returns a double value ({{Code|0.0}} - {{Code|1.0}}). The | + | |Computes the [https://en.wikipedia.org/wiki/Damerau%E2%80%93Levenshtein_distance Damerau-Levenshtein Distance] for two strings and returns a double value ({{Code|0.0}} - {{Code|1.0}}). The returned value is computed as follows:<br/> |
− | * <code>1.0 | + | * <code>1.0</code> – distance / max(length of strings) |
* <code>1.0</code> is returned if the strings are equal; <code>0.0</code> is returned if the strings are too different. | * <code>1.0</code> is returned if the strings are equal; <code>0.0</code> is returned if the strings are too different. | ||
|- | |- | ||
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* {{Code|strings:levenshtein("flower", "lewes")}} returns {{Code|0.5}} | * {{Code|strings:levenshtein("flower", "lewes")}} returns {{Code|0.5}} | ||
* In the following query, the input is first normalized (words are stemmed, converted to lower case, and diacritics are removed). It returns {{Code|1}}: | * In the following query, the input is first normalized (words are stemmed, converted to lower case, and diacritics are removed). It returns {{Code|1}}: | ||
− | < | + | <syntaxhighlight lang="xquery"> |
let $norm := ft:normalize(?, map { 'stemming': true() }) | let $norm := ft:normalize(?, map { 'stemming': true() }) | ||
return strings:levenshtein($norm("HOUSES"), $norm("house")) | return strings:levenshtein($norm("HOUSES"), $norm("house")) | ||
− | </ | + | </syntaxhighlight> |
|} | |} | ||
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The Module was introduced with Version 8.3. | The Module was introduced with Version 8.3. | ||
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Revision as of 15:44, 27 February 2020
This XQuery Module contains functions for string computations.
Contents
Conventions
All functions and errors in this module and errors are assigned to the http://basex.org/modules/strings
namespace, which is statically bound to the strings
prefix.
Functions
strings:levenshtein
Signatures | strings:levenshtein($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:
|
Examples |
<syntaxhighlight lang="xquery"> let $norm := ft:normalize(?, map { 'stemming': true() }) return strings:levenshtein($norm("HOUSES"), $norm("house")) </syntaxhighlight> |
strings:soundex
Signatures | strings:soundex($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 |
|
strings:cologne-phonetic
Signatures | strings: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 |
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Changelog
The Module was introduced with Version 8.3.