# Extract / Relocate Substring In ID3 Tags **URL:** \ **Category:** Support\ **Created:** [July 14, 2020, 11:05am UTC](https://community.mp3tag.de/t/extract-relocate-substring-in-id3-tags/49610 "2020-07-14T11:05:25Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![iamyou](https://community.mp3tag.de/letter_avatar_proxy/v4/letter/i/c68b51/32.png) [@iamyou](https://community.mp3tag.de/u/iamyou)\ **Post date:** [July 14, 2020, 11:05am UTC](https://community.mp3tag.de/t/extract-relocate-substring-in-id3-tags/49610/1 "2020-07-14T11:05:25Z")
I know this is a simple exercise, but I've hit a mental block 😔 I want to move parts of a ID3 tag, into different parts. * * * Input: Comment: Motown Records -- MTWN45 Output: Publisher: Motown Records Catalog #: MTWN45 * * * Basically, I want to work out the logic of moving strings from a tag, into different tags. This could be KEY and BPM information in the `%comments%`, but more importantly, in my case `%Publisher%` and `%catalog #%` . I can then also then do the reverse, e.g. move KEY and BPM information into `%comments%` like this: KEY - BPM , etc. There is usually a double minus/hyphen or on rare occassions, triple minus/hyphen separator, e.g - ABC XYZ -- xxx45 - ABC LMNOP --- xxx1234 I tried ACTION - GUESS Value Source: $regexp(%comment%,'.\*(?= -- )',$1) Guessing: %publisher% Source: $regexp(%comment%,'(?\<= -- ).\*',$1) Guessing: %catalog #% but this giving me some weird results. ---
**Author:** ![ohrenkino](https://community.mp3tag.de/user_avatar/community.mp3tag.de/ohrenkino/32/4843_2.png) [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)\ **Post date:** [July 14, 2020, 11:10am UTC](https://community.mp3tag.de/t/extract-relocate-substring-in-id3-tags/49610/2 "2020-07-14T11:10:06Z")
> [@iamyou](#): > > There is usually a double minus/hyphen or on rare occassions, triple minus/hyphen separator Try an action of the type "Guess value" Source: %comment% Guessing: %publisher% -- %catalog#% This action leaves the data as it is in COMMENT but fills the 2 additional fields. You may have to clear the COMMENT field afterwards. I would recommend either a filter or a unifying action to get the variation down to > [@iamyou](#): > > a double minus/hyphen ---
**Author:** ![iamyou](https://community.mp3tag.de/letter_avatar_proxy/v4/letter/i/c68b51/32.png) [@iamyou](https://community.mp3tag.de/u/iamyou)\ **Post date:** [July 14, 2020, 11:12am UTC](https://community.mp3tag.de/t/extract-relocate-substring-in-id3-tags/49610/3 "2020-07-14T11:12:30Z")
> [@ohrenkino](#): > > Try an action of the type "Guess value" > Source: %comment% > Guessing: %publisher% -- %catalog#% ^ I tried this exactly, before I made the post. It did not work. I did not mention this, because it was the most obvious thing to try ... and I'm learning some tricks,...but sorry, it did not work 😪 ---
**Author:** ![iamyou](https://community.mp3tag.de/letter_avatar_proxy/v4/letter/i/c68b51/32.png) [@iamyou](https://community.mp3tag.de/u/iamyou)\ **Post date:** [July 14, 2020, 11:14am UTC](https://community.mp3tag.de/t/extract-relocate-substring-in-id3-tags/49610/4 "2020-07-14T11:14:23Z")
sorry.... it does work ! I was hitting some blank space character, and it was not matching. Let me try a few more times.... ---
**Author:** ![iamyou](https://community.mp3tag.de/letter_avatar_proxy/v4/letter/i/c68b51/32.png) [@iamyou](https://community.mp3tag.de/u/iamyou)\ **Post date:** [July 14, 2020, 11:17am UTC](https://community.mp3tag.de/t/extract-relocate-substring-in-id3-tags/49610/5 "2020-07-14T11:17:24Z")
> [@ohrenkino](#): > > Try an action of the type "Guess value" > Source: %comment% > Guessing: %publisher% -- %catalog#% ^ this works. Bravo, ohrenkino 👍 MP3Tag was 'auto-completing' my expressions, and inserted a "wrong" string, so my matches were not working. It was my mistake & I feel embarrassed now. So, I used 2 x 'Guess Values' in consecutive order, within the same action. ie. 1) for picking up "--" matches 2) for picking up "---" matches ^ This works well ---
**Author:** ![ohrenkino](https://community.mp3tag.de/user_avatar/community.mp3tag.de/ohrenkino/32/4843_2.png) [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)\ **Post date:** [July 14, 2020, 11:23am UTC](https://community.mp3tag.de/t/extract-relocate-substring-in-id3-tags/49610/6 "2020-07-14T11:23:02Z")
> [@iamyou](#): > > So, I used 2 x 'Guess Values' in consecutive order, within the same action I would have used a simple "Replace" action to replace 3 hyphens with just 2 as this would have unified the contents of the COMMENT field. If I treat that field again, I would have to distinguish the 2 cases again. This would not be necessary if the COMMENT field contents would be unified. ---
**Author:** ![iamyou](https://community.mp3tag.de/letter_avatar_proxy/v4/letter/i/c68b51/32.png) [@iamyou](https://community.mp3tag.de/u/iamyou)\ **Post date:** [July 14, 2020, 11:31am UTC](https://community.mp3tag.de/t/extract-relocate-substring-in-id3-tags/49610/7 "2020-07-14T11:31:43Z")
Yes, I am aware of this. I am just cleaning up some tags now, and I will improve my future workflow, to unify some syntax. I was hitting some 'incorrect characters' before, with the "Guessing Values", so that's why I kept failing....and I am embarrassed by it now. ---
**Author:** ![system](https://community.mp3tag.de/uploads/default/original/2X/c/ce7035d426cb755a7916793326d23b465222a407.png) [@system](https://community.mp3tag.de/u/system)\ **Post date:** [February 9, 2026, 12:28pm UTC](https://community.mp3tag.de/t/extract-relocate-substring-in-id3-tags/49610/8 "2026-02-09T12:28:43Z")