CODEWITHSUNDEEP
macosswiftcocoacurrency
Geek20
Geek20

Reputation: 713

Get currency symbols from currency code with swift

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

Example:

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?

Upvotes: 40

Views: 39894

Answers (12)

dronpopdev
dronpopdev

Reputation: 817

I suggest a faster and more convenient solution. You can get all possible symbols for a specific currency:

Currency.currency(for: "USD")! // Currency(code: "USD", symbols: ["US$", "USD", "$"])
Currency.currency(for: "CAD")! // Currency(code: "USD", symbols: ["$", "CA$"])

Or get the shortest symbol. This is usually what everyone wants:

Currency.currency(for: "CAD")!.shortestSymbol // "$"

Now about the speed. The first call to this method takes linear time proportional to the number of locales plus the number of codes. Each subsequent call for any code is executed in constant time. Therefore, if you are implementing a CurrencyPickerViewController or something similar, then this solution is optimal.

Also, this solution has one more plus. Since global constants and variables are always computed lazily, if you never call a method to get information about the currency, the cache will not take up any memory.

struct Currency {
   
   /// Returns the currency code. For example USD or EUD
   let code: String
   
   /// Returns currency symbols. For example ["USD", "US$", "$"] for USD, ["RUB", "₽"] for RUB or ["₴", "UAH"] for UAH
   let symbols: [String]
   
   /// Returns shortest currency symbols. For example "$" for USD or "₽" for RUB
   var shortestSymbol: String {
      return symbols.min { $0.count < $1.count } ?? ""
   }
   
   /// Returns information about a currency by its code.
   static func currency(for code: String) -> Currency? {
      return cache[code]
   }
   
   // Global constants and variables are always computed lazily, in a similar manner to Lazy Stored Properties.
   static fileprivate var cache: [String: Currency] = { () -> [String: Currency] in
      var mapCurrencyCode2Symbols: [String: Set<String>] = [:]
      let currencyCodes = Set(Locale.commonISOCurrencyCodes)
      
      for localeId in Locale.availableIdentifiers {
         let locale = Locale(identifier: localeId)
         guard let currencyCode = locale.currencyCode, let currencySymbol = locale.currencySymbol else {
            continue
         }
         if currencyCode.contains(currencyCode) {
            mapCurrencyCode2Symbols[currencyCode, default: []].insert(currencySymbol)
         }
      }
      
      var mapCurrencyCode2Currency: [String: Currency] = [:]
      for (code, symbols) in mapCurrencyCode2Symbols {
         mapCurrencyCode2Currency[code] = Currency(code: code, symbols: Array(symbols))
      }
      return mapCurrencyCode2Currency
   }()
}

To see how this functionality works for all codes, you can use the code:

for code in Locale.commonISOCurrencyCodes {
   guard let currency = Currency.currency(for: code) else {
      // Three codes have no symbol. This is CUC, LSL and VEF
      print("Missing symbols for code \(code)")
      continue
   }
   print(currency)
}

Upvotes: 7

Bruno Garelli
Bruno Garelli

Reputation: 234

You can use static 'availableIdentifiers' collection, containing all posible identifiers as follows:

extension Locale {
    static func locale(from currencyIdentifier: String) -> Locale? {
        let allLocales = Locale.availableIdentifiers.map({ Locale.init(identifier: $0) })
        return allLocales.filter({ $0.currencyCode == currencyIdentifier }).first
    }
}

Upvotes: 2

iOS_Engineer
iOS_Engineer

Reputation: 11

let countryCode = (Locale.current as NSLocale).object(forKey: .currencySymbol) as? String ?? "$"

Above will give current currency Symbol, For UK it gives me = £ Apple Doc

Upvotes: 1

fs_tigre
fs_tigre

Reputation: 10738

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)")

Upvotes: 12

Gunhan
Gunhan

Reputation: 7035

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) }
}

Upvotes: 13

Pancho
Pancho

Reputation: 4143

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)
}

Upvotes: 46

Taku
Taku

Reputation: 5918

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

Upvotes: 17

Agent Smith
Agent Smith

Reputation: 2913

Swift 4 Version of Pancho's answer, As the String.characters is deprecated now.

We can simply apply dropLast() on String.

func getCurrencySymbol(from currencyCode: String) -> String? {

    let locale = NSLocale(localeIdentifier: currencyCode)
    if locale.displayName(forKey: .currencySymbol, value: currencyCode) == currencyCode {
        let newlocale = NSLocale(localeIdentifier: currencyCode.dropLast() + "_en")
        return newlocale.displayName(forKey: .currencySymbol, value: currencyCode)
    }
    return locale.displayName(forKey: .currencySymbol, value: currencyCode)
}

Upvotes: 2

that guy
that guy

Reputation: 203

SWIFT4 
//converting USD to $a and GBP to £ 
viewDidLoad() 
{ 
 print(getSymbolForCurrencyCode(code: "USD")!) // prints $ 
 print(getSymbolForCurrencyCode(code: "GBP")!) //prints £ 
}

func getSymbolForCurrencyCode(code: String) -> String? 
{ 
  let locale = NSLocale(localeIdentifier: code)
  return locale.displayName(forKey: NSLocale.Key.currencySymbol, value: code) 
}

Upvotes: 6

M-P
M-P

Reputation: 4959

An imperfect solution I found to get $ instead of US$ or CA$ was to attempt to match the user's current locale to the currency code first. This will work for situations where you're building a mobile app and an API is sending you currency code based on the settings in that user's account. For us the business case is that 99% of users have the same currency code set in their account on the backend (USD, CAD, EUR, etc.), where we're getting the information from, as they do on their mobile app where we're displaying currency the way a user would expect to see it (i.e. $50.56 instead of US$ 50.56).

Objective-C

- (NSLocale *)localeFromCurrencyCode:(NSString *)currencyCode {
    NSLocale *locale = [NSLocale currentLocale];
    if (![locale.currencyCode isEqualToString:currencyCode]) {
        NSDictionary *localeInfo = @{NSLocaleCurrencyCode:currencyCode};
        locale = [[NSLocale alloc] initWithLocaleIdentifier:[NSLocale localeIdentifierFromComponents:localeInfo]];
    }
    return locale;
}

Swift

func locale(from currencyCode: String) -> Locale {
    var locale = Locale.current
    if (locale.currencyCode != currencyCode) {
        let identifier = NSLocale.localeIdentifier(fromComponents: [NSLocale.Key.currencyCode.rawValue: currencyCode])
        locale = NSLocale(localeIdentifier: identifier) as Locale
    }
    return locale;
}

Upvotes: 5

Dave DeLong
Dave DeLong

Reputation: 243146

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$"

Upvotes: 14

MirekE
MirekE

Reputation: 11555

You can try this:

let formatter = NSNumberFormatter()

for locale in NSLocale.availableLocaleIdentifiers() {
    formatter.locale = NSLocale(localeIdentifier: locale)
    print("\(formatter.currencyCode) =  \(formatter.currencySymbol)")
}

Upvotes: 1

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