Can Locale identify country by currency code? - ios

Question

I was looking for that answer in here, and also on official documentation, but I can't find the answer for that. I've got currency codes (e.g. "EUR"). I need to get country code (e.g "EU"). So I've seen that I can do it inversely (getting currency code by using country code), but I was trying to change this solution for my needs, and I got nil as result. Also I know I can use simple solution - remove last letter from currency code to get country code (It works for most cases from my API data, but not everywhere) - but I feel this approach is not safe. So my question is like in title: Can I identify country from currency code by using Locale?
Here is my approach:
with NSLocale
extension NSLocale {
static func currencySymbolFromCode(code: String) -> String? {
let localeIdentifier = NSLocale.localeIdentifier(fromComponents: [NSLocale.Key.currencyCode.rawValue : code])
let locale = NSLocale(localeIdentifier: localeIdentifier)
return locale.object(forKey: NSLocale.Key.countryCode) as? String
}
}
with Locale
extension Locale {
static let countryCode: [String: String] = Locale.isoCurrencyCodes.reduce(into: [:]) {
let locale = Locale(identifier: Locale.identifier(fromComponents: [NSLocale.Key.currencyCode.rawValue: $1]))
$0[$1] = (locale.regionCode)
}
}

Answer 1

A currency can be associated with multiple countries, you should create your own custom data implementation, such as following json
{
"EUR":"PL",
"USD":"CA"
}
Create a file in your Xcode project and name it for e.g. data.json, and paste such JSON as above, finally use following method
func getCountryCode(currency: String) -> String? {
var countryCode: String?
let url = Bundle.main.url(forResource: "data", withExtension: "json")!
do {
let data = try Data(contentsOf: url)
let json = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as? [String: String]
countryCode = json?[currency]
} catch {
print(error.localizedDescription)
}
return countryCode
}
Usage
if let countryCode = getCountryCode(currency: "EUR") {
print(countryCode)
}

Answer 2

The answer from #AamirR is a bit not accurate.
EUR != PL, PL = PLN = Poland
USD != CA, CA = CAD = Canada
In majority of cases (with some exceptions), first 2 letters of currency code = ISO 3166-2 country code:
PLN = PL = Poland
GBP = GB = Great Britain
USD = US = United States of America
AMD = AM = Armenia
CZK = CZ = Czech Republic
BRL = BR = Brazilia
and so on ...
So if you have currency codes you can get country names (with 99% accuracy) as follows:
let currencyCode = "USD"
let countryCode = String(currencyCode.prefix(2))
let countryName = Locale.current.localizedString(forRegionCode: countryCode)
print(countryName)
Optional("United States")
However, as some commented above, EU for example, is not a country, and looks like in your specific case you do not need a country flag, you need "currency flag", so for EUR you will display EU flag, which is correct, as you cant determine which EU country flag to display - France, Germany, etc ... so this approach might work for mapping currencies to countries flags.
Though there are some exceptions, in terms of first 2 letters of currency code not matching first 2 letters of country name, from ISO 3166-2 country code perspective, they still match:
CHF = CH = Switzerland
HRK = HR = Croatia
DKK = DK = Denmark
... and so on
The other interesting pattern is that first 2 letters of currency codes, would usually match country internet domain, but again, there are some exceptions from this too.