filter rows with empty lists

hi all,

I use the GroupBy to aggregate data in a list and for some rows, the result will be an empty list .

Now I want to filter/separate rows, where the result column contains an empty list. The row filter only offers missing/not missing, which does not apply here; for the moment I resort to convert the list to a string and filter for the literal string (“[ ]”), but this seems awkward, as I want to maintain the list data type. Is there a more elegant approach?