# Generating a date from Year/Week (Day Of Week) **URL:** \ **Category:** Support\ **Created:** [May 25, 2014, 1:54pm UTC](https://community.mp3tag.de/t/generating-a-date-from-year-week-day-of-week/15765 "2014-05-25T13:54:34Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![dcassidy](https://community.mp3tag.de/letter_avatar_proxy/v4/letter/d/a88e57/32.png) [@dcassidy](https://community.mp3tag.de/u/dcassidy)\ **Post date:** [May 25, 2014, 1:54pm UTC](https://community.mp3tag.de/t/generating-a-date-from-year-week-day-of-week/15765/1 "2014-05-25T13:54:34Z")
I have a situation where the only date related information in an MP3 tag is a 4/6 charater field (or part thereof) indicating the Year and Week number. I would like to be able to generate an ISO Date from this information. Example: 201107 (or 1107) represents **Year: 2011** **Week: 7** and of course we would provide it with a variable (1-7) of the Day of the week e.g. Wednesday = 3. The calculation would return **2011-02-16** I tried several approaches which on my part didn;t get me very far such as Regex or the MP3Tag built in functions. Can anyone suggest an approach to take, Many thanks in advance, Desmond. ---
**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:** [May 25, 2014, 3:47pm UTC](https://community.mp3tag.de/t/generating-a-date-from-year-week-day-of-week/15765/2 "2014-05-25T15:47:32Z")
perhaps an export to a csv-file and a subsequent treatment in Excel (or some similar) which has a set of powerful date functions. If you google for the calender-week to date calculation, you find loads of examples. You can then re-import the result, if you saved it in Excel as text-file. ---
**Author:** ![DetlevD](https://community.mp3tag.de/user_avatar/community.mp3tag.de/detlevd/32/123_2.png) [@DetlevD](https://community.mp3tag.de/u/DetlevD)\ **Post date:** [May 26, 2014, 6:40am UTC](https://community.mp3tag.de/t/generating-a-date-from-year-week-day-of-week/15765/3 "2014-05-26T06:40:44Z")
> [@Dezzz](#): > > I have a situation where the only date related information in an MP3 tag is a 4/6 charater field (or part thereof) indicating the Year and Week number. I would like to be able to generate an ISO Date from this information. ... Mp3tag does not provide an easy way for mathematical calculation or conversion from year-week-day to year-month-day date values. But there is an easy way to solve the request by using a lookup-table. For example ... for the ywd-value "2014221" look into the table of the year 2014 ... and get the corresponding ymd-value "2014-05-26". Attached is an archive file with table files for each year from "1900" to "2100". Extract the table files from the archive file into the folder "%APPDATA%\Mp3tag\data". By extraction there should be created the subfolder "Tables.Ywd.Ymd", which contains the various table files. Create the action group ... Begin Action Group **Format DATE#Get ISO Date from YearWeekDaynumber** Action #1 _Actiontype 14:_ **Import text file** _Field \_\_:_ **DATE\_TABLE** _Filename:_ **$getEnv('MP3TAGAPPDATA')'\data\Tables.Ywd.Ymd\