# Filter expressions

**URL:** https://community.mp3tag.de/t/filter-expressions/10080
**Category:** Howto
**Created:** [March 11, 2010, 5:37pm UTC](https://community.mp3tag.de/t/filter-expressions/10080 "2010-03-11T17:37:11Z")
**Posts on this page:** 1
**Showing post:** 4

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### Author: ![dano](https://community.mp3tag.de/user_avatar/community.mp3tag.de/dano/32/6_2.png) [@dano](https://community.mp3tag.de/u/dano)
#### Post date: [March 16, 2010, 7:10pm UTC](https://community.mp3tag.de/t/filter-expressions/10080/4 "2010-03-16T19:10:57Z")

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### Filter with Regular Expression (Regex)

**Track numbers that have number/number syntax**  
`track MATCHES \d\/\d`

**Filenames that start with two digits:**  
`%_filename% MATCHES ^\d\d`

**Filenames that start with two digits not followed by another digit:**  
`%_filename% MATCHES ^\d\d\D`

**Case sensitive filter:**  
`title MATCHES (?-i)regex`

**Files with characters that are not in ISO-8859-1 in tag or filename**  
`* MATCHES [\x{0100}-\x{FFFF}]`

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