# Regex replace help for multi-value fields

**URL:** https://community.mp3tag.de/t/regex-replace-help-for-multi-value-fields/56856
**Category:** Support
**Created:** [March 29, 2022, 9:08pm UTC](https://community.mp3tag.de/t/regex-replace-help-for-multi-value-fields/56856 "2022-03-29T21:08:26Z")
**Posts on this page:** 1
**Showing post:** 2

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### Author: ![LyricsLover](https://community.mp3tag.de/letter_avatar_proxy/v4/letter/l/c6cbf5/32.png) [@LyricsLover](https://community.mp3tag.de/u/LyricsLover)
#### Post date: [March 29, 2022, 9:55pm UTC](https://community.mp3tag.de/t/regex-replace-help-for-multi-value-fields/56856/2 "2022-03-29T21:55:54Z")

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You are looking for an action which appends  
space`(Performer)`  
to any entry in your PERFORMER tag which not already have any value in brackets, right?

If you want to

> [@Zapgok](#):
>
> filter out these files correctly,

you could press F3 and enter  
`NOT PERFORMER MATCHES \(`  
this would show you all tracks where the PERFORMER tag doesn't include an opening bracket

You can find more examples here:

> [@Filter expressions](https://community.mp3tag.de/t/filter-expressions/10080):
>
> This topic collects useful Filter expressions If you have a useful filter expression, please post it here and give a short description of what it does. These filter expressions can be used with the Mp3tag filter [F3]. Please look at [https://docs.mp3tag.de/filter](https://docs.mp3tag.de/filter) for the documentation. Notes All filter keywords must be uppercase. All operations are case insensitive, for a workaround see [this post](https://community.mp3tag.de/t/10080/4).

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