Grouping list by object except one field I have to group list items if the items fields are the same. Above in my code, it works what I want if every id is the same. But product ids are unique. For that reason, I cant make the right grouping. I want to make grouping by item except for id. data class Product( val id: Int, val name: String, val price: Int, val quantity: Int ) data class GroupedProduct( val product: Product, val count: Int, val totalQuantity: Int, val isGroup: Boolean ) var products =...