Unicode collation algorithm: Difference between revisions

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{{Short description|String collation algorithm}}

The '''Unicode collation algorithm''' ('''UCA''') is an algorithm defined in Unicode Technical Report #10, which is a customizable method to produce binary keys from [[String (computer science)|strings]] representing text in any [[writing system]] and [[language]] that can be represented with [[Unicode]]. These keys can then be efficiently compared byte by byte in order to [[collate]] or sort them according to the rules of the language, with options for ignoring case, accents, etc.<ref name=":0">{{Cite web |last=Whistler |first=Ken |last2=Scherer |first2=Markus |last3=Davis |first3=Mark |author-link3=Mark Davis (Unicode) |date=2022-08-26 |title=UTS #10: Unicode Collation Algorithm |url=https://www.unicode.org/reports/tr10/ |access-date=2023-08-16 |website=[[Unicode]]}}</ref>

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The '''Unicode collation algorithm''' ('''UCA''') is an algorithm defined in Unicode Technical Report #10, which is a customizable method to produce binary keys from [[String (computer science)|strings]] representing text in any [[writing system]] and [[language]] that can be represented with [[Unicode]]. These keys can then be efficiently compared byte by byte in order to [[collate]] or sort them according to the rules of the language, with options for ignoring case, accents, etc.<ref name=":0">{{Cite web |lastlast1=Whistler |firstfirst1=Ken |last2=Scherer |first2=Markus |last3=Davis |first3=Mark |author-link3=Mark Davis (Unicode) |date=2022-08-26 |title=UTS #10: Unicode Collation Algorithm |url=https://www.unicode.org/reports/tr10/ |access-date=2023-08-16 |website=[[Unicode]]}}</ref>

Unicode Technical Report #10 also specifies the ''Default Unicode Collation Element Table'' (DUCET),. thisThis data file specifies a default collation ordering,. theThe DUCET is customizable for different languages.,<ref name=":0" /><ref name=":1">{{Cite book |last=Hosken |first=Martin |url=https://scriptsource.org/cms/scripts/render_download.php?format=file&media_id=..%2Fsites%2Fs%2Fmedia%2Fdatabase%2Fssproto%2Fentries%2Fpn%2Frn%2Fpnrnlhkrq9_sort_tutorial.pdf&filename=sort_tutorial.pdf |title=Unicode Sort Tailoring: Tutorial |date=2021-09-23 |publisher=[[SIL International|SIL Writing Systems Technology]] |edition=1.3 |pages=2–3 |format=PDF |access-date=2023-08-16}}</ref> Someand some such customizations can be found in the Unicode [[Common Locale Data Repository]] (CLDR).<ref>{{Cite web |title=CLDR Releases/Downloads |url=https://cldr.unicode.org/index/downloads |access-date=2023-08-16 |website=[[Common Locale Data Repository|Unicode CLDR]] |language=}}</ref>

An open source implementation of UCA is included with the [[International Components for Unicode]], ICU.<ref>{{Cite web |title=ICU - International Components for Unicode |url=https://icu.unicode.org/home |access-date=2023-08-16 |website=[[Unicode]]}}</ref><ref>{{Cite web |title=Collations |url=https://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.help.sqlanywhere.12.0.1/dbadmin/natlang-s-7003956.html |access-date=2023-08-16 |website=SyBooks Online}}</ref> ICU supports tailoring, and the collation tailorings from CLDR are included in ICU.<ref>{{Cite web |title=Customization |url=https://unicode-org.github.io/icu/userguide/collation/customization/ |access-date=2023-08-16 |website=ICU Documentation |language=}}</ref><ref name=":1" />

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===Tools===

* [https://icu4c-demos.unicode.org/icu-bin/locexp?_=en_US&x=col ICU Locale Explorer] An online demonstration of the Unicode Collation Algorithm using [[International Components for Unicode]], as of 2023-08-16 it's not working.

*[https://icu4c-demos.unicode.org/icu-bin/collation.html An ICU collation demo], as of 2023-08-16 it's not working.

* [http://billposer.org/Software/msort.html msort] A sort program that provides an unusual level of flexibility in defining collations and extracting keys.