# 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:** 5

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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: [December 6, 2010, 9:24am UTC](https://community.mp3tag.de/t/filter-expressions/10080/5 "2010-12-06T09:24:12Z")

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**Filenames with 2 hyphens**  
`"$len($regexp(%_filename%,'[^-]',))" IS 2`

**Filenames with at least 2 hyphens**  
`"$len($regexp(%_filename%,'[^-]',))" GREATER 1`

**Track number is a single digit**  
`track MATCHES ^\d$`

**Title tag starts with four capital letters**  
`"$if($eql($regexp(%title%,^\u\u\u\u,),%title%),yes,no)" IS no`

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