Sum of prices in an NSArray of items.

SumInNSArrayWithKeyValueCoding.swift

// Playground - noun: a place where people can play

import Foundation

class Item: NSObject {
    var name: String?
    var price: NSDecimalNumber?
    
    init(name: String, price: NSDecimalNumber) {
        self.name = name
        self.price = price
        super.init()
    }
}

let one = Item(name: "iPhone 5", price: NSDecimalNumber(string: "100"))
let two = Item(name: "iPhone 6", price: NSDecimalNumber(string: "200"))
let three = Item(name: "iPhone 6s", price: NSDecimalNumber(string: "300"))

let oldTypeOfArray: NSArray = [one, two, three]

let sum = oldTypeOfArray.valueForKeyPath("@sum.price")