Swift Array.insert generics

Question

func getIndex(valueToFind: T) -> Int? {...}

mutating func replaceObjectWithObject(obj1: T, obj2: T) {
    if let index =          


        

Answer 1

This answer is for a duplicate question stated her: Create swift array extension for typed arrays

There is a way to solve extensions to Array that are only applicable to a specific type of array. But you have to use an Array with elements of type Any, which sort of circumvents Swift's type system. But the code still works even if there are elements of other types in the array. See example below.

class Job {
    var name: String
    var id: Int
    var completed: Bool

    init(name: String, id: Int, completed: Bool) {
        self.name = name
        self.id = id
        self.completed = completed
    }
}

var jobs: [Any] = [
    Job(name: "Carpenter", id: 32, completed: true),
    Job(name: "Engineer", id: 123, completed: false),
    Job(name: "Pilot", id: 332, completed: true)]



extension Array {

    // These methods are intended for arrays that contain instances of Job

    func withId(id: Int) -> Job? {
        for j in self {
            if  (j as? Job)?.id == id {
                return j as? Job
            }
        }
        return nil
    }

    func thatAreCompleted() -> [Job] {
        let completedJobs =  self.filter { ($0 as? Job) != nil && ($0 as? Job)!.completed}
        return completedJobs.map { $0 as! Job }
    }
}

jobs.withId(332)
println(jobs.withId(332)?.name)
//prints "Optional("Pilot")"

let completedJobs = jobs.thatAreCompleted().map {$0.name}
println(completedJobs)
//prints "[Carpenter, Pilot]"