问题
LibreOffice Calc spreadsheet offers a function ISOWEEKNUM to return the standard ISO 8601 week number of the specified date.
I want the opposite.
➠ Given a standard week number, give me the date of the first day of that week (the Monday date).
Passing integers is acceptable. Also nice if able to pass a string in standard format.
Like this:
DATE_OF_ISOWEEKNUM( 2017 , 42 ) ➝ date of Monday of week 42 in week-based year 2017
DATE_OF_ISOWEEKNUM( "2017-W42" ) ➝ date of Monday of week 42 in week-based year 2017
Ideally, I would be able to pass a number 1-7 for Monday-Sunday to specify the day-of-week for which I want a date. Something like this:
DATE_OF_ISOWEEKNUM( 2017 , 42 , 1 ) ➝ date of Monday of week 42 in week-based year 2017
DATE_OF_ISOWEEKNUM( "2017-W42-1" ) ➝ date of Monday of week 42 in week-based year 2017
DATE_OF_ISOWEEKNUM( 2017 , 42 , 7 ) ➝ as above, but Sunday
DATE_OF_ISOWEEKNUM( "2017-W42-7" ) ➝ as above, but Sunday
回答1:
Example:
Formula:
=DATE(B$1,1,$A4*7)+(2-WEEKDAY(DATE(B$1,1,$A4*7)))-7*(ISOWEEKNUM(DATE(B$1,1,1))=1)
- Calculate the date of day (weeknumber * 7) in the year.
- Correct the day to be weekday Monday.
- Correct to 7 days before, if the first day of the year is in the first ISO weeknumber.
来源：https://stackoverflow.com/questions/45392608/given-an-iso-8601-week-number-get-date-of-first-day-of-that-week-in-libreoffice