You can sort-of do it: add week name dimension to the sheet - by default Sunday will be the first day. Right-click the dimension pill and select sort, then opt for manual sort at the bottom and just drag the days around in whatever order you need.
Unfortunately you will have to repeat this procedure every time you add week name to a sheet, but the alternative involves some complex date calculations, etc..
Thanks for that Dimitri - I had tried that previously but the issue is that it just shifts the ending Saturday to the start of the week - eg First week of Jan just shifts Saturday 7 to the beginning of the week when really it should be Saturday 31 Dec and then the next week should start on the 7th instead.
What was the complex date calculation option?
What would be the criteria to pick the first week of the year?
By ISO standard it is the week with the first Thursday of the year (with the idea that at least 4 out of 7 days of the week must belong to the year), with the week starting on Monday.
The conventional week numbering system starts first week on January 1, whatever day of week it might be, and makes the first week and every other week (except the last week of the year) last till Sunday (or Saturday, depending on the locale), so the first and last weeks usually have less than 7 days.
I can probably come up with a custom formula to start week numbering from Saturday, but need a definition of first week.
See attached workbook for an example custom calculation for Sat-Fri week, with 1st week being one with 1st Tuesday of the year.
custom_week_number.twbx 95.9 KB