# Regular Expression
**URL:** https://community.mp3tag.de/t/regular-expression/13874
**Category:** General Discussion
**Created:** [September 13, 2012, 7:48pm UTC](https://community.mp3tag.de/t/regular-expression/13874 "2012-09-13T19:48:34Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@cldcp00](https://community.mp3tag.de/u/cldcp00)
#### Post date: [September 13, 2012, 7:48pm UTC](https://community.mp3tag.de/t/regular-expression/13874/1 "2012-09-13T19:48:34Z")
Could somebody point me in the right direction. I am cleaning up my tags and I have lots of tags that have the following stuture
01 - Filename
344 Filename
. Filename
-
```
Filename
```
Are there expressions which will clean the tags up to leave just the filename.
Where can I learn to write expressions?
Thanks in advance for you help
---
### Author:  [@JJ\_Johnson](https://community.mp3tag.de/u/JJ_Johnson)
#### Post date: [September 13, 2012, 7:53pm UTC](https://community.mp3tag.de/t/regular-expression/13874/2 "2012-09-13T19:53:58Z")
If you have tags (fields) with those structures and want the values to be equal to the filename, then you don't need to use a regular expression. You can just set the tag to the filename using a format value action.
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### Author:  [@cldcp00](https://community.mp3tag.de/u/cldcp00)
#### Post date: [September 13, 2012, 7:58pm UTC](https://community.mp3tag.de/t/regular-expression/13874/3 "2012-09-13T19:58:31Z")
Thats ok with a small number of the tags, but the majority have the title or artist missing thats why I need an expressions
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### Author:  [@JJ\_Johnson](https://community.mp3tag.de/u/JJ_Johnson)
#### Post date: [September 13, 2012, 8:02pm UTC](https://community.mp3tag.de/t/regular-expression/13874/4 "2012-09-13T20:02:16Z")
It's hard to tell what you're trying to do. The following site is a pretty good guide to regular expressions.
[http://www.regular-expressions.info](http://www.regular-expressions.info)
---
### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [September 14, 2012, 3:46am UTC](https://community.mp3tag.de/t/regular-expression/13874/5 "2012-09-14T03:46:50Z")
> [@Dego](#):
>
> Thats ok with a small number of the tags, but the majority have the title or artist missing thats why I need an expressions
An expression is tailor-made to fit one particular pattern. So it would be much easier to point you into a direction if you could supply examples as close to reality as possible.
E.g. if you have a TITLE that looks like this:
344 Filename
you could apply an action to remove the 344 with a replace action.
If you have a TITLE that looks like this
01 - Filename
you can perform an action of the type "Guess values" and the pattern
%track% - %title%.
But this is just guesswork. Please be more specific.