Return 1 for current week -1 in calculated column

[Anonymous]

Hi All, 

I have a calendar table below and I have a year week column that does not correspond to the normal weeknum formula as our week dates for the calendar is different. I would like to have a column stating "1" to show the YearWeek for last week. For e.g. this week is W32, i would like to show one week prior, W31, as "1". This is so that when i am showing my graph, it always shows the previous week as i would like to use this column to filter. 

[Fowmy · Accepted solution]

@Anonymous 
Add the following column:

Last Week = 
IF(
    YEAR(TODAY()-7) * 100 + WEEKNUM(TODAY()-7) = [Year Week],
    1
)

[amitchandak]

@Anonymous , expected output is not clear. Based on what I got so far

Week Type = Switch( True(),
weeknum([Date],1) && weeknum(Today()-7,1) ,1 ,
0
)