How to get country name from currency code?

Question

How to get country name from currency code? Is this possible or not?

Answer 1

Alternative option, using Swift 3 Locale class data:

struct CurrencyToRegionMapper {

    static let locales = Locale.availableIdentifiers.map(Locale.init)

    static func locales(currencyCode: String) -> Set<Locale> {
        let localesWithCode = self.locales.filter { locale in
            locale.currencyCode == currencyCode
        }
        return Set(localesWithCode)
    }

    static func locales(currencySymbol: String) -> Set<Locale> {
        let localesWithSymbol = self.locales.filter { locale in
            locale.currencySymbol == currencySymbol
        }
        return Set(localesWithSymbol)
    }

    static func regionNames(currencyCode: String, forLocale locale: Locale = Locale.autoupdatingCurrent) -> Set<String> {
        let locale = Locale(identifier: locale.identifier) // .current and .autoupdatingCurrent doesn't work without this hack for some reason
        let localesForCode = self.locales(currencyCode: currencyCode)
        let names: [String] = localesForCode.flatMap { loc in
            if let regionCode = loc.regionCode {
                return locale.localizedString(forRegionCode: regionCode)
            } else {
                return locale.localizedString(forIdentifier: loc.identifier)
            }
        }
        return Set(names)
    }

    static func regionNames(currencySymbol: String, forLocale locale: Locale = Locale.autoupdatingCurrent) -> Set<String> {
        let locale = Locale(identifier: locale.identifier) // .current and .autoupdatingCurrent doesn't work without this hack for some reason
        let localesForSymbol = self.locales(currencySymbol: currencySymbol)
        let names: [String] = localesForSymbol.flatMap { loc in
            if let regionCode = loc.regionCode {
                return locale.localizedString(forRegionCode: regionCode)
            } else {
                return locale.localizedString(forIdentifier: loc.identifier)
            }
        }
        return Set(names)
    }

}

Usage:

CurrencyToRegionMapper.locales(currencyCode: "EUR") // Returns set of locales, where currency is Euro
CurrencyToRegionMapper.locales(currencySymbol: "$") // Returns set of locales, where currency symbol is $

CurrencyToRegionMapper.regionNames(currencyCode: "GBP", forLocale: Locale(identifier: "en_POSIX")) // Returns set of regions(countries) names which use british pound in POSIX locale: ["United Kingdom", "Guernsey", "Jersey", "Isle of Man"]
CurrencyToRegionMapper.regionNames(currencySymbol: "¥", forLocale: Locale(identifier: "fi_FI")) // Returns set of regions which use currency with symbol ¥ in Finnish locale: ["Kiina", "Japani"]