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FrankT Frequent Visitor
Frequent Visitor

Date.DayOfWeek - Default for argument firstDayOfWeek ???

According to the documentation the default for the argument firstDayOfWeek should be Day.Sunday!

 

October 31st, 2010 was a Sunday but Date.DayOfWeek(#date(2010,10,31)) returns 6.

Has this argument somehow been localized? Here in Germany the week starts on Monday, thus 6 would correctly represent a Sunday for Day.Monday.

 

 

Date.DayOfWeek(dateTime as any, optional firstDayOfWeek as nullable number) as nullable number


Returns a number between 0 and 6 representing the day of the week in the provided datetime value dateTime. This function takes an optional Day value, firstDayOfWeek, to set the first day of the week for this relative calculation. The default value firstDay is Day.Sunday. Valid values are: Day.Sunday, Day.Monday, Day.Tuesday, Day.Wednesday, Day.Thursday, Day.Friday, and Day.Saturday.
  • dateTime: A date, datetime, or datetimezone value from which the day of the week is determined.

  • firstDayOfWeek: A Day type representing the first day of the week for this calculation.

1 ACCEPTED SOLUTION

Accepted Solutions
Super User
Super User

Re: Date.DayOfWeek - Default for argument firstDayOfWeek ???

The documentation is incorrect.

 

It is the first day of the week according to your regional settings in Windows.

 

You may consider always specifying the first day of the week instead of relying on the default.

 

Specializing in Power Query Formula Language (M)
2 REPLIES 2
Super User
Super User

Re: Date.DayOfWeek - Default for argument firstDayOfWeek ???

The documentation is incorrect.

 

It is the first day of the week according to your regional settings in Windows.

 

You may consider always specifying the first day of the week instead of relying on the default.

 

Specializing in Power Query Formula Language (M)
Redoute Frequent Visitor
Frequent Visitor

Re: Date.DayOfWeek - Default for argument firstDayOfWeek ???

= Date.DayOfWeek(#date(2018, 10, 23)) = Day.Monday

TRUE

 

And I thought it is tuesday already Smiley Sad