Can you share more details on what you are trying to accomplish and what you’ve tried?
There’s some examples in the original Health and Battery Reports thread that’s a good starting point:
When in doubt, I would also recommend reading the expressions documentation, especially the linked General Functions reference:
As you’ll note from the original example, the filter(array, expression) filters to items that return true for the expression. So to do the original exclusion example linked above, we are adding a not() to invert things… so an inclusion is basically the same thing without a not()