# Regular Expression assistance
**URL:** https://community.mp3tag.de/t/regular-expression-assistance/945
**Category:** General Discussion
**Created:** [March 31, 2004, 10:59pm UTC](https://community.mp3tag.de/t/regular-expression-assistance/945 "2004-03-31T22:59:07Z")
**Posts on this page:** 10
**Page:** 1
### Author:  [@Logan](https://community.mp3tag.de/u/Logan)
#### Post date: [March 31, 2004, 10:59pm UTC](https://community.mp3tag.de/t/regular-expression-assistance/945/1 "2004-03-31T22:59:07Z")
Ok, need a little help here....
First off, anyone know of a good Regular Expression tutorial ? I'd like to learn how to do this myself...
While I dig around for one, would appreciate it if someone could enlighten me as to how I do the followig :
- search for x-x and replace with x - x where x is any character
- change the string _track - artist - title (pres artist2) (mix\_name)_ to _track - artist pres artist2 - title (mix\_name)_
Fun facts about the second one :
- 'track' and '(mix\_name)' are optional
- 'pres' may be 'feat' or 'vs.' - but all files will have one of the three
I would **_greatly_** appreciate any assistance offered.
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### Author:  [@dano](https://community.mp3tag.de/u/dano)
#### Post date: [April 1, 2004, 6:39am UTC](https://community.mp3tag.de/t/regular-expression-assistance/945/2 "2004-04-01T06:39:12Z")
1:
(.)-(.)
$1 - $2
2:
^(\d{1,2}\s-\s)?(._)\s-\s(._)\s((._))(\s(._))?
$1$2 $4 - $3$5
Mp3tag helpfile is good
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### Author:  [@Logan](https://community.mp3tag.de/u/Logan)
#### Post date: [April 5, 2004, 7:27pm UTC](https://community.mp3tag.de/t/regular-expression-assistance/945/3 "2004-04-05T19:27:21Z")
Thanks for the help d4n0, but the second one didn't quite work.
Your suggestion resulted in :
track - artist mix\_name - title (pres artist2)
when I am looking for :
track - artist pres artist2 - title (mix\_name)
When I broke the results down into $1 - $2 - $3 - $4 - $5, it does not appear to be seperating the string _title (pres artist2)_ into two compenents.
I checked the help file as you suggested, but apparently I am daft...
Any more suggestions ?
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### Author:  [@dano](https://community.mp3tag.de/u/dano)
#### Post date: [April 5, 2004, 8:29pm UTC](https://community.mp3tag.de/t/regular-expression-assistance/945/4 "2004-04-05T20:29:37Z")
i have no clue why title (pres artist2) is always together ☹
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### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [April 6, 2004, 7:28am UTC](https://community.mp3tag.de/t/regular-expression-assistance/945/5 "2004-04-06T07:28:05Z")
Check the greedyness of the repeats in the parenthesis part. The regular expression
**^(\d{1,2}\s-\s)?(._)\s-\s(._)\s((._?))(\s(._?))**
should work.
Best regards,
~ Florian
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### Author:  [@dano](https://community.mp3tag.de/u/dano)
#### Post date: [April 6, 2004, 7:43am UTC](https://community.mp3tag.de/t/regular-expression-assistance/945/6 "2004-04-06T07:43:09Z")
it does not work when there is no (mix\_name) at the end
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### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [April 6, 2004, 7:58am UTC](https://community.mp3tag.de/t/regular-expression-assistance/945/7 "2004-04-06T07:58:37Z")
Oh yes, you're right! I've changed all repeats to be non-greedy in your regular expression and now it should work for both cases.
**^(\d{1,2}\s-\s)?(._?)\s-\s(._?)\s((._?))(\s(._))?**
**$1$2 $4 - $3$5**
Best regards,
~ Florian
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### Author:  [@dano](https://community.mp3tag.de/u/dano)
#### Post date: [April 6, 2004, 1:10pm UTC](https://community.mp3tag.de/t/regular-expression-assistance/945/8 "2004-04-06T13:10:14Z")
awesome, yes seems to be fine now
and i gotta find out what greedyness exactly is 😃
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### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [April 6, 2004, 1:37pm UTC](https://community.mp3tag.de/t/regular-expression-assistance/945/9 "2004-04-06T13:37:30Z")
> [@](#):
>
> and i gotta find out what greedyness exactly is 😃
You can translate greedyness with "Gierigkeit". Greedy (standard) repeats are eating as much characters as possible - the non-greedy ones (those with the question mark after the repeat character) don't 🙂
~ Florian
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### Author:  [@Logan](https://community.mp3tag.de/u/Logan)
#### Post date: [April 6, 2004, 4:32pm UTC](https://community.mp3tag.de/t/regular-expression-assistance/945/10 "2004-04-06T16:32:49Z")
you guys rock....