Question

如何在swift中从JSON中检索的数字中添加逗号。

Example
31908551587 to
31,908,551,587

我很困惑，我不知道该怎么做。

Answer 1

您可以使用NSNumberFormatter

执行此操作

Swift 4

let largeNumber = 31908551587
let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = .decimal
let formattedNumber = numberFormatter.string(from: NSNumber(value:largeNumber))

Swift 3

 let largeNumber = 31908551587
 let numberFormatter = NumberFormatter()
 numberFormatter.numberStyle = NumberFormatter.Style.decimal
 let formattedNumber = numberFormatter.string(from: NSNumber(value:largeNumber))

Swift 2

 let largeNumber = 31908551587
 let numberFormatter = NSNumberFormatter()
 numberFormatter.numberStyle = NSNumberFormatterStyle.DecimalStyle
 let formattedNumber = numberFormatter.stringFromNumber(largeNumber)

Answer 2

扩展ÖzgürErsil的答案，你可以通过对Int的扩展来隔离功能：

extension Int {
    func withCommas() -> String {
        let numberFormatter = NumberFormatter()
        numberFormatter.numberStyle = NumberFormatter.Style.decimal
        return numberFormatter.string(from: NSNumber(value:self))!
    }
}

然后在代码中使用：

largeNumber.withCommas()

Answer 3

同样扩展Juan Fran Jimenez的答案，我建议将格式化程序放入单例中，因为实例化格式化程序通常是一种相对昂贵的操作。（如果您在用户写入时随时进行格式化，则可能会影响性能。）

extension Int {

    private static var commaFormatter: NumberFormatter = {
        let formatter = NumberFormatter()
        formatter.numberStyle = .decimal
        return formatter
    }()

    internal var commaRepresentation: String {
        return Int.commaFormatter.string(from: NSNumber(value: self)) ?? ""
    }
}

Answer 4

一个简单的扩展，它将通过Int的扩展名提供变量。

如Julien的回答所述，出于性能原因，这会使用静态格式化程序。

extension Int {
    private static var numberFormatter: NumberFormatter = {
        let numberFormatter = NumberFormatter()
        numberFormatter.numberStyle = .decimal

        return numberFormatter
    }()

    var delimiter: String {
        return Int.numberFormatter.string(from: NSNumber(value: self)) ?? ""
    }
}

使用它：

let number = 31908551587
print(number.delimiter) // 31,908,551,587

Answer 5

这是设置逗号位置的另一种方法。让我们说我希望将数字10000000打印为＆＃34; 1,00,00,000＆＃34;

let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = .decimal
numberFormatter.groupingSize = 3
numberFormatter.secondaryGroupingSize = 2
numberFormatter.string(from: 10000000)

Answer 6

我为金额文本字段创建了一个类。只需将其设置为您的textfield类。输入1234567。它将转换为1,234,567 也适用于十进制输入，十进制后需要两位数字。

class AmountField: UITextField {

private var isFirstDecimal : Bool = true
override func willMove(toSuperview newSuperview: UIView?) {

    addTarget(self, action: #selector(editingChanged), for: .editingChanged)
    keyboardType = .decimalPad
    textAlignment = .left
    placeholder = "0.0"
    editingChanged()
}
override func deleteBackward() {
    var currentText = self.text ?? ""
    currentText = String(currentText.dropLast())
    self.text = currentText
    editingChanged(self)
}
@objc func editingChanged(_ textField: UITextField? = nil) {
    var doubleStr = textField?.text ?? "00"


    let decimalCount = doubleStr.components(separatedBy: ".")
    if decimalCount.count > 2 {
        var currentText = self.text ?? ""
        currentText = String(currentText.dropLast())
        self.text = currentText
        return
    }

    if doubleStr.contains(".") && isFirstDecimal == true {
        self.text = doubleStr
        isFirstDecimal = false
        return
    }
    else if !(doubleStr.contains(".")) {
        isFirstDecimal = true
    }

    let doubleStrTemp = doubleStr.replacingOccurrences(of: ",", with: "")

    if doubleStrTemp != "" {
        if let n = Decimal(string: doubleStrTemp )?.significantFractionalDecimalDigits {
            if n > 2 {
                var currentText = self.text ?? ""
                currentText = String(currentText.dropLast())
                self.text = currentText
                return
            }
        }
    }
    doubleStr = doubleStr.replacingOccurrences(of: ",", with: "")

    let doube = Double(doubleStr)
    let numberFormatter = NumberFormatter()
    numberFormatter.numberStyle = NumberFormatter.Style.decimal
    if doube != nil {
        let formattedNumber = numberFormatter.string(from: NSNumber(value:doube!))
        self.text = formattedNumber
    }
}}

extension Decimal {
var significantFractionalDecimalDigits: Int {
    return max(-exponent, 0)
}}

Answer 7

快捷键4

let largeNumber = 31908551587
let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = .decimal
let formattedNumber = numberFormatter.string(from: NSNumber(value:largeNumber))

如何在swift中向一个数字添加逗号？

7 个答案: