```
val avgs = products.averageBy(
key...
# announcementsp
poohbar
04/30/2018, 6:26 PM Copy code
val avgs = products.averageBy(
keySelector = { listOf(it.category, it.sectionId, it.regionId, it.customerId) },
doubleSelector = { it.defectRate }
)🤔 1