NSSortDescriptor in Swift

Question

I am working on an iOS app and I have data stored in CoreData that I am loading into a UITableView. The data entities have an attribute called id which is a string

Answer 1

Why to bother with obj-c style's NSSortDescriptor, In swift we can nicely sort using Swift high order functions - xcode 8.x swift 3.x

class Person: NSObject {
    let firstName: String
    let lastName: String
    let age: Int

    init(firstName: String, lastName: String, age: Int) {
        self.firstName = firstName
        self.lastName = lastName
        self.age = age
    }
    override var description: String {
        return "\(firstName) \(lastName)"
    }
}

let a = Person(firstName: "a", lastName: "b", age: 24)
let b = Person(firstName: "c", lastName: "d", age: 27)
let c = Person(firstName: "e", lastName: "f", age: 33)
let d = Person(firstName: "g", lastName: "h", age: 31)
let peopleObject = [d, b, a, c]
//SWIFTY
let sortedByFirstNameSwifty =  peopleObject.sorted(by: { $0.firstName < $1.firstName })
print(sortedByFirstNameSwifty)//prints[a b, c d, e f, g h]


//Objective c way
let firstNameSortDescriptor = NSSortDescriptor(key: "firstName", ascending: true, selector: #selector(NSString.localizedStandardCompare(_:)))
let sortedByFirstName = (peopleObject as NSArray).sortedArray(using: [firstNameSortDescriptor])
print(sortedByFirstName)//prints [a b, c d, e f, g h]