Sort Two Arrays of Different Types into One

Question

I have two arrays, they are of two different objects, and both contain an ID field. What I need to do is display them in order in a table view controller. They share the sam

Answer 1

Alternatively to Zoff Dino answer if you do not want to burden TypeA and TypeB classes with HasID protocol then you can define extension to these classes in your view controller:

class TypeA {
    var ID: Int

    init(_ id: Int) {
        self.ID = id
    }
}

class TypeB {
    var ID: Int

    init(_ id: Int) {
        self.ID = id
    }
}

protocol HasID {
    var ID: Int { get }
}

// place this in your view controller

extension TypeA: HasID {
}

extension TypeB: HasID {
}

var arrayA = [TypeA(1), TypeA(3), TypeA(5)]
var arrayB = [TypeB(2), TypeB(4)]

let sortedArray = (arrayA.map { $0 as HasID } + arrayB.map { $0 as HasID })
                      .sort { $0.ID < $1.ID }

Answer 2

Put all common properties into a protocol, the build and sort an array of that common protocol:

protocol HasID {
    var id: Int { get }
}

class TypeA : HasID, CustomStringConvertible {
    var id: Int

    init(_ id: Int) {
        self.id = id
    }

    var description : String {
        return ("TypeA(\(self.id))")
    }
}

class TypeB : HasID, CustomStringConvertible {
    var id: Int

    init(_ id: Int) {
        self.id = id
    }

    var description : String {
        return ("TypeB(\(self.id))")
    }
}

let typeA = [TypeA(1), TypeA(2), TypeA(5), TypeA(6)]
let typeB = [TypeB(3), TypeB(4), TypeB(7)]
let result: [HasID] = (typeA + typeB).sorted { $0.id < $1.id }

print(result)

[TypeA(1), TypeA(2), TypeB(3), TypeB(4), TypeA(5), TypeA(6), TypeB(7)] 

Answer 3

You can do this like so:

class TypeA {
    var ID: Int

    init(_ id: Int) {
        self.ID = id
    }
}

class TypeB {
    var ID: Int

    init(_ id: Int) {
        self.ID = id
    }
}

struct Wrap {
    var ID: Int {
        return a?.ID ?? b?.ID ?? 0
    }
    let a: TypeA?
    let b: TypeB?
}

var arrayA = [TypeA(1), TypeA(3), TypeA(5)]
var arrayB = [TypeB(2), TypeB(4)]

let sortedArray = (arrayA.map { Wrap(a: $0, b: nil) } + arrayB.map { Wrap(a: nil, b: $0)})
                      .sorted { $0.ID < $1.ID }

When row is selected you can determine object with:

if let a = sortedArray[index].a {
    // TypeA row selected
} else if let b = sortedArray[index].b {
    // TypeB row selected
}