# Filter operations may be case sensitive.
**URL:** https://community.mp3tag.de/t/filter-operations-may-be-case-sensitive/10077
**Category:** Support
**Created:** [March 11, 2010, 5:03am UTC](https://community.mp3tag.de/t/filter-operations-may-be-case-sensitive/10077 "2010-03-11T05:03:25Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@incifinci](https://community.mp3tag.de/u/incifinci)
#### Post date: [March 11, 2010, 5:03am UTC](https://community.mp3tag.de/t/filter-operations-may-be-case-sensitive/10077/1 "2010-03-11T05:03:25Z")
[Filtering files and tags (Searching)](https://docs.mp3tag.de/filter):
QUOTE (Mp3tag online help)
All operations are non-case sensitive.
Workaround: you can use the case sensitive function **$strstr()**.
Example: find files with " **i**" (wich must be written in uppercase in English) in title tag.
Filter expression: **"$if($grtr($strstr(%title%,' i '),0),1,0)" IS 1**
Slower, but more exact way for this special case - it finds " **i**" at start or end, too:
Filter expression:
**"$if($grtr($strstr($regexp(%title%,\b\x{69}\b,_lowercase\_I_),_lowercase\_I_),0),1,0)" IS 1**
_Not a big problem, but the second expression, sorry, matches "Ku-u-i-po" too.
I tried:
**"$if($grtr($strstr($regexp(%title%,[^.-]\b\x{69}\b[^.-],lowercase\_I),lowercase\_I),0),1,0)" IS 1**
...but it didn't work.
It's very interesting because this works:
%title% MATCHES [^.-]\bi\b[^.-]
(I mean, it don't match "Ku-u-i-po" - but, of course, case insensitive.)_
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### Author:  [@dano](https://community.mp3tag.de/u/dano)
#### Post date: [March 11, 2010, 5:30pm UTC](https://community.mp3tag.de/t/filter-operations-may-be-case-sensitive/10077/2 "2010-03-11T17:30:49Z")
Easier with regex switch:
title MATCHES (?-i)i
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### Author:  [@incifinci](https://community.mp3tag.de/u/incifinci)
#### Post date: [March 11, 2010, 6:48pm UTC](https://community.mp3tag.de/t/filter-operations-may-be-case-sensitive/10077/3 "2010-03-11T18:48:47Z")
It doesn't work at me. ☹ Matches all songs with **i** in title (about 50 % of all files).
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### Author:  [@dano](https://community.mp3tag.de/u/dano)
#### Post date: [March 11, 2010, 8:34pm UTC](https://community.mp3tag.de/t/filter-operations-may-be-case-sensitive/10077/4 "2010-03-11T20:34:59Z")
I see you want the i as word or surrounded by spaces..
title MATCHES "(?-i) i "
title MATCHES "(?-i)\bi\b"
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### Author:  [@incifinci](https://community.mp3tag.de/u/incifinci)
#### Post date: [March 12, 2010, 4:42am UTC](https://community.mp3tag.de/t/filter-operations-may-be-case-sensitive/10077/5 "2010-03-12T04:42:35Z")
Perfect! Thank you, dano.
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### Author:  [@system](https://community.mp3tag.de/u/system)
#### Post date: [February 9, 2026, 12:22pm UTC](https://community.mp3tag.de/t/filter-operations-may-be-case-sensitive/10077/6 "2026-02-09T12:22:14Z")