Using random on swift

I am a beginner on swift and I have tried to use random but I have this error:

Cannot subscript a value of type '[String]' with an argument of type 'UInt32'

I don't understand why. Here is my code:

import UIKit

class ViewController: UIViewController {

    var Person = ["jean Michel" , "antoine roubet" , "samuel demets" , "zater burkov", "Gochnik samuel"]

    var city = ["De Paris","De Monreal","Du Maroc","De Tunis","De sarcelles","De roubaix"]

    @IBOutlet weak var quoteLabel: UILabel!

    @IBAction func changeQuote() {

        var randomIndex = arc4random_uniform(UInt32(Person.count))
        var thePerson = Person[randomIndex]
        print(thePerson)

        var randomIndex2 = arc4random_uniform(UInt32(city.count))
        var theCity = city[randomIndex2]
        print(theCity)

        quoteLabel.text = "le texte est modifié"

    }
}