# Regex expression to transform dates
**URL:** https://community.mp3tag.de/t/regex-expression-to-transform-dates/67436
**Category:** Support
**Created:** [February 9, 2025, 6:58am UTC](https://community.mp3tag.de/t/regex-expression-to-transform-dates/67436 "2025-02-09T06:58:08Z")
**Posts on this page:** 12
**Page:** 1
### Author:  [@GeorgeW](https://community.mp3tag.de/u/GeorgeW)
#### Post date: [February 9, 2025, 6:58am UTC](https://community.mp3tag.de/t/regex-expression-to-transform-dates/67436/1 "2025-02-09T06:58:08Z")
Greetings,
I have struggled to swap the operation of this format expression
[Regular Expressions - #46 by DetlevD](https://community.mp3tag.de/t/regular-expressions/521/46)?
to achieve this
2009-02-03 to 03 Feb 2009
Would appreciate any help from regex experts
Thanks
George
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### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [February 9, 2025, 7:21am UTC](https://community.mp3tag.de/t/regex-expression-to-transform-dates/67436/2 "2025-02-09T07:21:39Z")
You do not say in which field you find the date.
Try an action of the type "Format value" or Convert\>Tag-Tag for the unnamed field
Format string: `$regexp('2009-02-03',\d+-\d+-(\d+),$1) $replace($regexp('2009-02-03',\d+-(\d+)-\d+,$1),01,Jan,02,Feb) $regexp('2009-02-03',(\d+)-\d+-\d+,$1)`
in which you also replace `'2009-02-03'` with the fieldname.
And you have to complete the translation of month numbers into month names. I was too lazy to write all 12 and just showed 01 for Jan and 02 for Feb
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### Author:  [@GeorgeW](https://community.mp3tag.de/u/GeorgeW)
#### Post date: [February 9, 2025, 7:40am UTC](https://community.mp3tag.de/t/regex-expression-to-transform-dates/67436/3 "2025-02-09T07:40:00Z")
Thank you, I will try this. I have been using a Comment field as my experiment field, but ultimately I want to split filename (2003-03-01-SomeTextFollows) into the Title field as 01 Mar 2003 - Some Text Follows. I have managed to achieve the text extraction and conversion and am happy I can achieve the concatenation of date and text once I have converted date format.
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### Author:  [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [February 9, 2025, 7:45am UTC](https://community.mp3tag.de/t/regex-expression-to-transform-dates/67436/4 "2025-02-09T07:45:40Z")
I would use Convert\>Filename-Tag with
Format string: %year% - %title%
to get the data from the filename into the fields YEAR and TITLE
and then use this structured data to adapt the format.
Finally, you can re-write the filename with Convert\>Tag-Filename (if still required).
Also, you can copy the YEAR data to TITLE with
Convert\>Tag-Tag for TITLE
Format string: %year% - %title%
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### Author:  [@GeorgeW](https://community.mp3tag.de/u/GeorgeW)
#### Post date: [February 9, 2025, 8:32am UTC](https://community.mp3tag.de/t/regex-expression-to-transform-dates/67436/5 "2025-02-09T08:32:01Z")
The final tested solution.
Convert 2009-03-02 to 2 Mar 2009
~~`$regexp(%yourfield%,\d+-\d+-(\d+),$1) $replace($regexp(%yourfield%,\d+-(\d+)-\d+,1),01,Jan,02,Feb,03,Mar,04,Apr,05,May,06,Jun,07,Jul,08,Aug,09,Sep,10,Oct,11,Nov,12,Dec) $regexp(%yourfield%,(\d+)-\d+-\d+,$1)`~~
Thank you @ohrenkino for your guidance
> [@GeorgeW](#):
>
> Could you please correct in my solution, I appear be unable to edit.
`$regexp(%yourfield%,\d+-\d+-(\d+),$1) $replace($regexp(%yourfield%,\d+-(\d+)-\d+,$1),01,Jan,02,Feb,03,Mar,04,Apr,05,May,06,Jun,07,Jul,08,Aug,09,Sep,10,Oct,11,Nov,12,Dec) $regexp(%yourfield%,(\d+)-\d+-\d+,$1)`
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### Author:  [@LyricsLover](https://community.mp3tag.de/u/LyricsLover)
#### Post date: [February 12, 2025, 11:24am UTC](https://community.mp3tag.de/t/regex-expression-to-transform-dates/67436/6 "2025-02-12T11:24:09Z")
> [@GeorgeW](#):
>
> $regexp(%yourfield%,\d+-\d+-(\d+),$1) $replace($regexp(%yourfield%,\d+-(\d+)-\d+,1),01,Jan,02,Feb,03,Mar,04,Apr,05,May,06,Jun,07,Jul,08,Aug,09,Sep,10,Oct,11,Nov,12,Dec) $regexp(%yourfield%,(\d+)-\d+-\d+,$1)
Are you sure that this should work as expected?
If I try it with 2009-03-02 in a COMMENT field and this regular expression:
`$regexp(%COMMENT%,\d+-\d+-(\d+),$1) $replace($regexp(%COMMENT%,\d+-(\d+)-\d+,1),01,Jan,02,Feb,03,Mar,04,Apr,05,May,06,Jun,07,Jul,08,Aug,09,Sep,10,Oct,11,Nov,12,Dec) $regexp(%COMMENT%,(\d+)-\d+-\d+,$1)`
I get as result `02 1 2009` and not the expected `2 Mar 2009`
Even If I fix the replacement from `01,Jan` to `1,Jan` I only get `02 Jan 2009` as result.
BTW:
The regular expression started from @ohrenkino would work for the March example:
`$regexp(%COMMENT%,\d+-\d+-(\d+),$1) $replace($regexp(%COMMENT%,\d+-(\d+)-\d+,$1),01,Jan,02,Feb,03,Mar) $regexp(%COMMENT%,(\d+)-\d+-\d+,$1)` and results in the expected `02 Mar 2009`
(please note the leading zero for the day)
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### Author:  [@LyricsLover](https://community.mp3tag.de/u/LyricsLover)
#### Post date: [February 12, 2025, 11:32am UTC](https://community.mp3tag.de/t/regex-expression-to-transform-dates/67436/7 "2025-02-12T11:32:50Z")
This regular expression would work - at least for the number-to-month replacement.
`$regexp(%COMMENT%,\d+-\d+-(\d+),$1) $replace($regexp(%COMMENT%,\d+-(\d+)-\d+,$1),01,Jan,02,Feb,03,Mar,04,Apr,05,May,06,Jun,07,Jul,08,Aug,09,Sep,10,Oct,11,Nov,12,Dec) $regexp(%COMMENT%,(\d+)-\d+-\d+,$1)`
But it still convert YYYY-MM-DD in DD MMM YYYY (with a leading zero in front of the day).
`2009-03-02` becomes `02 Mar 2009`
If the expected result should show the days 01 to 09 without leading zero, then you would need an additional `$num` around the number of days, something like
`$num($regexp(%COMMENT%,\d+-\d+-(\d+),$1),1)`...
The complete regular expression to
> [@GeorgeW](#):
>
> Convert 2009-03-02 to 2 Mar 2009
would look like this:
`$num($regexp(%COMMENT%,\d+-\d+-(\d+),$1),1) $replace($regexp(%COMMENT%,\d+-(\d+)-\d+,$1),01,Jan,02,Feb,03,Mar,04,Apr,05,May,06,Jun,07,Jul,08,Aug,09,Sep,10,Oct,11,Nov,12,Dec) $regexp(%COMMENT%,(\d+)-\d+-\d+,$1)`
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### Author:  [@GeorgeW](https://community.mp3tag.de/u/GeorgeW)
#### Post date: [February 12, 2025, 9:45pm UTC](https://community.mp3tag.de/t/regex-expression-to-transform-dates/67436/8 "2025-02-12T21:45:45Z")
@LyricsLover
Apologies, you are right, there is a missing $ here, for the 1 variable at end of this string.
$regexp(%year%,\d+-\d+-(\d+),$1) $replace($regexp(%year%,\d+-(\d+)-\d+,$1) ....
Could you please correct in my solution, I appear be unable to edit.
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### Author:  [@GeorgeW](https://community.mp3tag.de/u/GeorgeW)
#### Post date: [February 12, 2025, 9:49pm UTC](https://community.mp3tag.de/t/regex-expression-to-transform-dates/67436/9 "2025-02-12T21:49:26Z")
@LyricsLover
Agree that my expression does not remove leading zero for single digit day values, but I didn't see that as an issue, was so happy to achieve transformation 😄
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### Author:  [@LyricsLover](https://community.mp3tag.de/u/LyricsLover)
#### Post date: [February 12, 2025, 10:42pm UTC](https://community.mp3tag.de/t/regex-expression-to-transform-dates/67436/10 "2025-02-12T22:42:00Z")
> [@GeorgeW](#):
>
> Could you please correct in my solution, I appear be unable to edit.
I'm not sure why you are unable to click on the
icon and edit your own solution.
But I hope I have fixed it (please double check it).
> [@GeorgeW](#):
>
> but I didn't see that as an issue
This is not a big issue, I have only added this version for future readers.
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### Author:  [@GeorgeW](https://community.mp3tag.de/u/GeorgeW)
#### Post date: [February 12, 2025, 11:09pm UTC](https://community.mp3tag.de/t/regex-expression-to-transform-dates/67436/11 "2025-02-12T23:09:41Z")
Editing of Solution not allowed? I don't see the pencil symbol on my Solution post, but I do see it on my other posts in this thread.
Solution is correct now, thank you
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### Author:  [@system](https://community.mp3tag.de/u/system)
#### Post date: [March 14, 2025, 11:10pm UTC](https://community.mp3tag.de/t/regex-expression-to-transform-dates/67436/12 "2025-03-14T23:10:10Z")
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