ios - NumberFormatter 和货币字符串的欧元错误

Question

我在 Swift 中编写了一个函数(字符串扩展)来获取任何货币字符串，例如“$500.00”或“250,75 €”，甚至“500”，然后从中返回一个 nsdecimalnumber。

不幸的是，当我传入“250,75 €”时，它命中了我代码的 if (nf.number(from: self) == nil) 部分并评估为 nil，因此什么也不返回。它似乎只在您用逗号添加更改时发生，例如 250,75。但是，如果我做了 250，它就会起作用。它似乎只为欧元这样做。美元运作良好($500.00、125.75 等)

这是我的代码。有什么想法吗？感谢您的宝贵时间!

extension String{
func toDecimalFromCurrencyString() -> NSDecimalNumber
    {

        let nf = NumberFormatter()
        nf.numberStyle = NumberFormatter.Style.currency
        nf.formatterBehavior = NumberFormatter.Behavior.behavior10_4
        nf.generatesDecimalNumbers = true

        var test = self.replacingOccurrences(of: nf.currencySymbol!, with: "", options: NSString.CompareOptions.literal, range: nil)
        test = test.replacingOccurrences(of: nf.currencyDecimalSeparator!, with: "", options: NSString.CompareOptions.literal, range: nil)
        test = test.replacingOccurrences(of: nf.currencyGroupingSeparator!, with: "", options: NSString.CompareOptions.literal, range: nil)
        let scanner: Scanner = Scanner(string:test)
        let isNumeric = (scanner.scanDecimal(nil) && scanner.isAtEnd)

        //If the string entered isn't numeric (for example ... or $$$, then fail)
        if (self.trimmingCharacters(in: CharacterSet.whitespaces).utf16.count == 0 || (!isNumeric))
        {
            return 0.0
        }
        //If the string contains more than one decimal separator (.), or more than one currency symbol ($), return 0.0
        else if ((self.components(separatedBy: nf.currencyDecimalSeparator!).count-1) > 1 || (self.components(separatedBy: nf.currencySymbol!).count - 1) > 1) {
            return 0.0
        }
        //If the string contains more than one consecutive currency grouping separator (i.e. ,,) then return 0.0
        else if ((components(separatedBy: nf.currencyGroupingSeparator! + nf.currencyGroupingSeparator!).count-1) > 0)
        {
            return 0.0
        }
        else
        {
            if (nf.number(from: self) == nil) {
                return 0.00
            }
            else {
                return nf.number(from: self) as! NSDecimalNumber
            }
        }
    }


}

Answer 1

您可以简单地从字符串中删除所有非数字并使用两个数字格式化程序，一个带点，另一个带逗号，并在链中使用 nil 合并运算符，如下所示:

extension Formatter {
    static let decimalWithDotSeparator: NumberFormatter = {
        let numberFormatter = NumberFormatter()
        numberFormatter.numberStyle = .decimal
        numberFormatter.decimalSeparator = "."
        return numberFormatter
    }()
    static let decimalWithCommaSeparator: NumberFormatter = {
        let numberFormatter = NumberFormatter()
        numberFormatter.numberStyle = .decimal
        numberFormatter.decimalSeparator = ","
        return numberFormatter
    }()
}

extension String {
    var numberFromCurrency: NSDecimalNumber? {
        var string = self
        while let first = string.characters.first, Int("\(first)") == nil {
            string = String(string.characters.dropFirst())
        }
        while let last = string.characters.last, Int("\(last)") == nil {
            string = String(string.characters.dropLast())
        }
        return (Formatter.decimalWithDotSeparator.number(from: string) ??
                Formatter.decimalWithCommaSeparator.number(from: string) ?? 0)
                .decimalValue.decimalNumber
    }
}

extension Decimal {
    var decimalNumber: NSDecimalNumber { return NSDecimalNumber(decimal: self) }
}

---

let dollar = "$249.99"
dollar.numberFromCurrency   // 249.99

let real = "R$249,99"
real.numberFromCurrency   // 249.99

let euro = "0,50€"
euro.numberFromCurrency    // 0.5