Get currency symbols from currency code with swift

Question

How can I get the currency symbols for the corresponding currency code with Swift (macOS).

Example:

• EUR = €1.00
• USD = $1.00
• CAD = $1.00
• GBP = £1.00

My code:

var formatter = NSNumberFormatter()
formatter.currencySymbol = getSymbol(currencyCode)
formatter.numberStyle = NSNumberFormatterStyle.CurrencyStyle
let number = NSNumber(double: (amount as NSString).doubleValue)
let amountWithSymbol = formatter.stringFromNumber(number)!

getSymbol(_ currencyCode: String) -> String

or.. is there a better way?

Solution 1

A bit late but this is a solution I used to get the $ instead of US$ etc. for currency symbol.

/*
 * Bear in mind not every currency have a corresponding symbol. 
 *
 * EXAMPLE TABLE
 *
 * currency code | Country & Currency | Currency Symbol
 *
 *      BGN      |   Bulgarian lev    |      лв   
 *      HRK      |   Croatian Kuna    |      kn
 *      CZK      |   Czech  Koruna    |      Kč
 *      EUR      |       EU Euro      |      €
 *      USD      |     US Dollar      |      $
 *      GBP      |   British Pound    |      £
 */

func getSymbol(forCurrencyCode code: String) -> String? {
   let locale = NSLocale(localeIdentifier: code)
   return locale.displayNameForKey(NSLocaleCurrencySymbol, value: code)
}

Basically this creates NSLocale from your currency code and grabs the display attribute for the currency. In cases where the result matches the currency code for example SEK it will create new country specific locale by removing the last character from the currency code and appending "_en" to form SE_en. Then it will try to get the currency symbol again.

Swift 3 & 4

func getSymbol(forCurrencyCode code: String) -> String? {
    let locale = NSLocale(localeIdentifier: code)
    if locale.displayName(forKey: .currencySymbol, value: code) == code {
        let newlocale = NSLocale(localeIdentifier: code.dropLast() + "_en")
        return newlocale.displayName(forKey: .currencySymbol, value: code)
    }
    return locale.displayName(forKey: .currencySymbol, value: code)
}

Solution 2

The answer may be late but hopefully this helps clarify the root cause.

Problem

• Currency code does not imply locale and region

The reason why CAD becomes CA$ is probably because NSLocale looks up the first matching currency code, and for CAD, these are the matching localeIdentifiers in order of NSLocale.availableLocaleIdentifiers

1. Optional("CA$") Optional("CA") iu_CA
2. Optional("$") Optional("CA") fr_CA
3. Optional("$") Optional("CA") en_CA

iu_CA is Inuktitut but I'm not sure why it's listed as CA$, but I hope the point is clear.

Similarly in CNY (Chinese Yuan):

1. Optional("CN¥") Optional("CN") en_CN
2. Optional("¥") Optional("CN") yue_CN
3. Optional("¥") Optional("CN") bo_CN
4. Optional("¥") Optional("CN") zh_CN
5. Optional("￥") Optional("CN") ug_CN
6. Optional("¥") Optional("CN") ii_CN

The reason for showing CN¥ when en_CN is probably because JPY also uses ¥.

In CHF (Switzerland Franc), they do not have a one-letter symbol:

1. Optional("CHF") Optional("LI") gsw_LI
2. Optional("CHF") Optional("CH") de_CH
...
9. Optional("CHF") Optional("CH") en_CH
10. Optional("CHF") Optional("CH") it_CH

Solution

Many apps vary, but this is the steps I took that I am happy with for my application:

1. Find matching locale candidates using currency code lookup from all locale identifiers
2. Pick the shortest symbol from the candidates
3. Store the symbol somewhere so that it doesn't have to be computed each time

Implementation

func getSymbolForCurrencyCode(code: String) -> String {
    var candidates: [String] = []
    let locales: [String] = NSLocale.availableLocaleIdentifiers
    for localeID in locales {
        guard let symbol = findMatchingSymbol(localeID: localeID, currencyCode: code) else {
            continue
        }
        if symbol.count == 1 {
            return symbol
        }
        candidates.append(symbol)
    }
    let sorted = sortAscByLength(list: candidates)
    if sorted.count < 1 {
        return ""
    }
    return sorted[0]
}

func findMatchingSymbol(localeID: String, currencyCode: String) -> String? {
    let locale = Locale(identifier: localeID as String)
    guard let code = locale.currencyCode else {
        return nil
    }
    if code != currencyCode {
        return nil
    }
    guard let symbol = locale.currencySymbol else {
        return nil
    }
    return symbol
}

func sortAscByLength(list: [String]) -> [String] {
    return list.sorted(by: { $0.count < $1.count })
}

Usage

let usd = getSymbolForCurrencyCode(code: "USD")
let jpy = getSymbolForCurrencyCode(code: "JPY")
let cny = getSymbolForCurrencyCode(code: "CNY")
let cad = getSymbolForCurrencyCode(code: "CAD")
let uah = getSymbolForCurrencyCode(code: "UAH")
let krw = getSymbolForCurrencyCode(code: "KRW")
let zar = getSymbolForCurrencyCode(code: "ZAR")
let chf = getSymbolForCurrencyCode(code: "CHF")
let all = [usd, jpy, cny, cad, uah, krw, zar, chf]

(lldb) po all
▿ 8 elements
  - 0 : "$"
  - 1 : "¥"
  - 2 : "¥"
  - 3 : "$"
  - 4 : "₴"
  - 5 : "₩"
  - 6 : "R"
  - 7 : "CHF"

Problems

1. Instinctively, I see that the one letter symbol approach can show an incorrect symbol if there are more than one distinct symbols for currency code, but I haven't seen such case.
2. Computing this each time is heavy lifting so when a user sets their currency setting, it's wise to store the computed result and use that result upon each lookup

Solution 3

The proper way to do this is to let the frameworks provide the information for you.

You can retrieve that information using an obscure class method on NSLocale called localeIdentifierFromComponents(). That method will take a dictionary that defines various attributes of your locale, and then returns an identifier you can use to actually construct an NSLocale instance. Once you have the NSLocale, you can ask it for its CurrencySymbol, like this:

let currencyCode = "CAD"

let localeComponents = [NSLocaleCurrencyCode: currencyCode]
let localeIdentifier = NSLocale.localeIdentifierFromComponents(localeComponents)
let locale = NSLocale(localeIdentifier: localeIdentifier)
let currencySymbol = locale.objectForKey(NSLocaleCurrencySymbol) as! String
// currencySymbol is "CA$"

Solution 4

I combined and improved all the suggestion here to have a drop-in(copy/paste) solution for the future readers(you).

It has its own local cache, case insensitive, and have an extension method to provide chaining for String. Swift 4/5 ready.

How to use:

"USD".currencySymbol //returns "$"
//OR
Currency.shared.findSymbol(currencyCode: "TRY") //returns "₺"

Tests:

    XCTAssertEqual("$", "USD".currencySymbol)
    XCTAssertEqual("₺", "TRY".currencySymbol)
    XCTAssertEqual("€", "EUR".currencySymbol)
    XCTAssertEqual("", "ASDF".currencySymbol)

Code:

class Currency {
    static let shared: Currency = Currency()

    private var cache: [String:String] = [:]

    func findSymbol(currencyCode:String) -> String {
        if let hit = cache[currencyCode] { return hit }
        guard currencyCode.count < 4 else { return "" }

        let symbol = findSymbolBy(currencyCode)
        cache[currencyCode] = symbol

        return symbol
    }

    private func findSymbolBy(_ currencyCode: String) -> String {
        var candidates: [String] = []
        let locales = NSLocale.availableLocaleIdentifiers

        for localeId in locales {
            guard let symbol = findSymbolBy(localeId, currencyCode) else { continue }
            if symbol.count == 1 { return symbol }
            candidates.append(symbol)
        }

        return candidates.sorted(by: { $0.count < $1.count }).first ?? ""
    }

    private func findSymbolBy(_ localeId: String, _ currencyCode: String) -> String? {
        let locale = Locale(identifier: localeId)
        return currencyCode.caseInsensitiveCompare(locale.currencyCode ?? "") == .orderedSame
            ? locale.currencySymbol : nil
    }
}

extension String {
    var currencySymbol: String { return Currency.shared.findSymbol(currencyCode: self) }
}

Solution 5

To simply get the currency symbol in Swift.

let locale = Locale.current // currency symbol from current location
//let locale = Locale(identifier: "fr_FR") // or you could specify the locale e.g fr_FR, en_US etc
let currencySymbol = locale.currencySymbol!

print("\(currencySymbol)")

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