convert week number into data

[yuval86]

Hello,

I have a week number (1,2,...,52) and I have the year, I'm looking for a function that could transform\convert the week and the year into date.

for some reason I didn't manage to do that.

Tank you..:)

[wgarn]

Another way is to insert a new new column (Power BI desktop >> New Measure >> New Column)

ndate = DATE([year],1,-2)-WEEKDAY(DATE([year],1,3))+[week]*7

 This is based on the ISO week date, which means we need to find the Monday nearest to the 1st of January.

[Anonymous]

Thanks, this is great and brief.

[maijanen]

Hello @wgarn ! This would actually solve the issue I have had but the code you had there returns Expression.Error DATE was not recocnized. Do you know the reason? Same actually comes with WEEKDAY.

[MarcelBeug]

@wgarn ISO Week Number 1 is the week (Mo-Su) that contains the 4th of January.

For the correct rules check (the comments below) my video.

Edit: ah, you mean Monday closest to January 1st is the start of week 1?

That looks like another correct way of formulating ISO week 1.

[ImkeF]

Do you expect to create one date per week (if yes: which one? First, last?) or all days?

[yuval86]

Yes, one data per week- the first day.

Thanks!

[ImkeF · Accepted solution]

 As I'm not aware of a function that returns the date of the week, instead I'd create a calendar for the year (replace "YourYear" respectively), create the week numbers and their first dates. Then filter on your week-numbers:

let
    Source = {Number.From(#date(YourYear,01,01))..Number.From(#date(YourYear,12,31))},
    #"Converted to Table" = Table.FromList(Source, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
    #"Changed Type" = Table.TransformColumnTypes(#"Converted to Table",{{"Column1", type date}}),
    WeekColumn = Table.AddColumn(#"Changed Type", "Week", each Date.WeekOfYear([Column1])),
    StartOfWeek = Table.AddColumn(WeekColumn, "StartOfWeek", each Date.StartOfWeek([Column1])),
    #"Filtered Rows1" = Table.SelectRows(StartOfWeek, each [Week] >= List.Min(YourWeekList) and [Week] <= List.Min(YourWeekList))
in
    #"Filtered Rows1"

[RichXM655]

Apologies for resurrecting an old thread, but i've implemented this solution and it's hit a snag - The code generates a column of tables as it should but when I then try and insert a step after it to expand out the "startofweek" column, I get an error: 

"gaweek" is the name of the "week" column in my source data which is drawn from Google Analytics (which I replaced the "yourweeklist" tags with in the supplied code as I think I was supposed to.)

[yuval86]

great, it was vary helpful.