How to add values from one to another data class? is it actually possible to connect two data classes by ID and then copy a value if IDs are equal?? data class Discount( val ID:String,val discountPrice:String) data class Catalog( val ID:String,val price:String, name:String, desc:String, discountPrice:String?) Catalog has over 4000 items and I need to copy discountPrice from Discount class to that Catalog..