How to have set analysis calculation obey current selection

[Anonymous]

Say I have an expression like so:

Sum({<[Type]={'A'}>}Cost)

I also have a list box for [Type]. And [Type] has A,B,C, etc. I noticed that even if I select [Type]='B' from the list box, the expression above still calculates. Is it possible to have the expression calculate a zero being that Type=A is not part of current selection?

[Chanty4u]

may be this?

Sum({1<[Type]={'A'}>}Cost)

[jwjackso]

Try Sum({$<[Type]={'A'}*P([Type])>}Cost)

[Peter_Cammaert · Accepted solution]

The set expression that you use starts from the current selection, but overrides the selection for field Type by forcibly setting it to value 'A'. By specifying the set expression [Type]={'A'}, you are effectively undoing the selection in field Type and putting a new one in place. All other current selections will remain unchanged.

To accomplish what you want, you can use combination operators like -= or *=. The latter is especally useful as it means (temporarily) assign to the field the intersection of the current selection with whatever I specify between braces. Example:

=Sum({<[Type] *= {'A'}>} Cost)

will throw away all currently selected Type values except for value 'A'. If value 'A' wasn't selected to begin with, it will stay unselected in this expression.