How to dynamically assign a variable based on filter selection

[Sony]

Hi Team, I'm new to QlikSense. I have a filter pane of Months from January to December. I want to assign the variable value based on filter selection.

 If February is selection in the filter pane, the variable  value should be assigned to its previous month i.e., January.

How to write the expression for above described variable. Can anyone please help me?

Thank you

[BenjaminT · Accepted solution]

If you need this to work when only a single Month is selected, something like the following should work:

=date(addmonths(date(date#(only(Month), 'MMMM')),-1), 'MMMM')

This is assuming that your [Month] field is jus a text string

Hope this helps

[wcoleman0908]

I believe the request was to set a variable  value based on the filter selection.