DAX measure to calculate previous 4 week number considering year change

[Anonymous]

Hello

I am trying to calculate and show a range of week numbers in a Power BI card visualization but the problem is that with the year change (week 52 going forwards to week 1) i want to always show the previous week number and the previous 4 weeks number. For example, it is currently week number 50. I want to show the range week number 46-49 in the card visualization. In 2022, if it is week 2, then the range should show: 50-1.

So, here is what i have done for the previous week number:

PreviousWeekNumber = WEEKNUM(TODAY(),21) - 1

And to find the previous 4 weeks number:

3 Weeks Before Previous Week Number = 
return IF([PreviousWeekNumber] == 1, 49, [PreviousWeekNumber]-3)
IF[PreviousWeekNumber] == 2, 50, [PreviousWeekNumber]-3)
IF([PreviousWeekNumber] == 3, 51, [PreviousWeekNumber]-3)
IF([PreviousWeekNumber] == 4, 52, [PreviousWeekNumber]-3)

But the latter is not working. I am new to Power BI. Any help is much appreciated!!

[AlexisOlson · Accepted solution]

You can rewrite your 3 Weeks expression with a SWITCH:

3 Weeks Before Previous Week Number =
VAR W = [PreviousWeekNumber]
RETURN
    SWITCH (
        W,
        1, 49,
        2, 50,
        3, 51,
        4, 52,
        W - 3
    )

Personally, I'd try using modular arithmetic:

3 Weeks Before Previous Week Number =
MOD ( WEEKNUM ( TODAY (), 21 ) - 5, 52 ) + 1