Find whether two Swift Arrays contain the same elements

Question

I have two arrays

let a1 = [obj1, obj2, obj3]
let a2 = [obj3, obj2, obj1]

Assume that the array elements are custom objects which are

Answer 1

If the items are unique and equatable (as in your example), convert to a Set and compare the Sets:

let a1 = [1, 2, 3]
let a2 = [3, 2, 1]
Set(a1) == Set(a2)

With some futzing, this can be made to work for an arbitrary class:

class Person : NSObject {
    let name: String
    init(name:String) {self.name = name}
    override func isEqual(other: AnyObject?) -> Bool {
        return other is Person && (other as! Person).name == self.name
    }
    override var hashValue : Int {
        return self.name.hashValue
    }
}

let a1 = [Person(name:"Matt"), Person(name:"Sam")]
let a2 = [Person(name:"Sam"), Person(name:"Matt")]
Set(a1) == Set(a2)