# Using rexexp on multiple tag fields **URL:** \ **Category:** Support\ **Created:** [September 11, 2014, 9:57am UTC](https://community.mp3tag.de/t/using-rexexp-on-multiple-tag-fields/16126 "2014-09-11T09:57:39Z")\ **Posts on this page:** 1\ **Showing post:** 5
**Author:** ![DetlevD](https://community.mp3tag.de/user_avatar/community.mp3tag.de/detlevd/32/123_2.png) [@DetlevD](https://community.mp3tag.de/u/DetlevD)\ **Post date:** [September 14, 2014, 6:30am UTC](https://community.mp3tag.de/t/using-rexexp-on-multiple-tag-fields/16126/5 "2014-09-14T06:30:14Z")
> [@pastim](#): > > ... It would make life much easier if all non-ASCII characters were converted to ASCII in the sorted form. I know this is possible, character by character, but there are an awful lot when all European languages are included. If mp3tag had a function to do this (eg $to\_ascii) it would make the actions an awful lot shorter and simpler. The current $ansi function doesn't do the same job. ... You can try ... regular expression equivalent classes ... for example ... $regexp('ÀÁÂÃÄÅĀĂĄ','[[=A=]]','A') ==\> AAAAAAAAA $regexp('a, á, à and â','[[=a=]]','a') ==\> "a, a, a and a" $regexp('e, é, è and ê','[[=e=]]','e') ==\> "e, e, e and e" $regexp('i, Í, ì and î','[[=i=]]','i') ==\> "i, i, i and i" $regexp('o, ó, ò and ô','[[=o=]]','o') ==\> "o, o, o and o" $regexp('u, ú, ù and û','[[=u=]]','u') ==\> "u, u, u and u" Equivalence classes An expression of the form [[=col=]], matches any character or collating element whose primary sort key is the same as that for collating element col, as with collating elements the name col may be a symbolic name. A primary sort key is one that ignores case, accentation, or locale-specific tailorings; so for example [[=a=]] matches any of the characters: a, À, Á, Â, Ã, Ä, Å, A, à, á, â, ã, ä and å. Unfortunately implementation of this is reliant on the platform's collation and localisation support; this feature can not be relied upon to work portably across all platforms, or even all locales on one platform. [http://www.boost.org/doc/libs/1\_44\_0/libs/...erl\_syntax.html](http://www.boost.org/doc/libs/1_44_0/libs/regex/doc/html/boost_regex/syntax/perl_syntax.html) You can try ... Mp3tag action groups for "Unicode to ASCII" ... [/t/7279/1](https://community.mp3tag.de/t/7279/1) DD.20140914.1030.CEST --- _[View the full topic](https://community.mp3tag.de/t/using-rexexp-on-multiple-tag-fields/16126)._