UIPicker set value based on description

I'm building a UIPickerView very similar to what we have in the post 3 Component Dynamic Multi UIPickerView Swift.

My code is

Class Country

import UIKit

class Country { 
var name: String 
var cities: [City]

init(name:String, cities:[City]) {
    self.name = name
    self.cities = cities
}
}

Class City

    import UIKit

class City { 
   var name: String 

init(name:String) {
    self.name = name
}
}

ViewController

class ViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource {

@IBOutlet weak var pickerView: UIPickerView!
@IBOutlet weak var countryLbl: UILabel!

var countries = [Country]()
var newOrExisting = "New"

override func viewDidLoad() {

    pickerView.delegate = self
    pickerView.dataSource = self

    countries.append(Country(name: "UK", cities: [City(name: "London"),City(name: "Manchester"), City(name: "Bristol")]))
    countries.append(Country(name: "USA", cities: [City(name: "New York"),City(name: "Chicago")]))
    countries.append(Country(name: "China", cities: [City(name: "Beijing"),City(name: "Shanghai"), City(name: "Shenzhen"), City(name: "Hong Kong")]))

    super.viewDidLoad()
    if newOrExisting == "Existing" {
    // here I need to load existing Country and City to the UIPickerView (for example, USA and Chigado) based on their names
    // newOrExisting status is updated in another ViewController. For example, let's assume it came as "existing"
    }


}

func numberOfComponents(in pickerView: UIPickerView) -> Int {
    return 2
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {

    if component == 0 {
        return countries.count
    } else  {
        let selectedCountry = pickerView.selectedRow(inComponent: 0)
        return countries[selectedCountry].cities.count
    } 
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    if component == 0 {
        return countries[row].name
    } else {
        let selectedCountry = pickerView.selectedRow(inComponent: 0)
        return countries[selectedCountry].cities[row].name
    } 
}

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    pickerView.reloadAllComponents

    let selectedCountry = pickerView.selectedRow(inComponent: 0)
    let selectedCity = pickerView.selectedRow(inComponent: 1)
    let cityR = countries[selectedCountry].cities[selectedCity].name

    countryLbl.text = "The right answer was: \(selectedCountry) in \(cityR)"

}
}

Note: I haven't added my comments there because, as I have less than 50 reputations, I cannot comment.

With the above code, I can add data to my UIPickerView and read data from it. I then store that data to a Firebase database. There I'll have, for example, Country name "USA" and the City name "Chicago".

But, I now need to do the opposite path. If I read "USA" and "Chicago" from the database, how do I select those in the UIPickerView just using their names? I don't have the indexes in my database. Is there a way to do it?

Thanks