Formatting Numbers in Swift 3

问题

I want to format number to this: 123.234.234.234 from 123234234234 depends on what the user types into the text field. I don't want to manage currency, it's not about currency, it is about the user has to type in a number and this number should be formatted correctly to be easier to read.

Not with a comma, with a dot.

I found only currency stuff in the whole research

回答1:

What you are looking for is probably groupingSeparator of NumberFormatter

let formater = NumberFormatter()
formater.groupingSeparator = "."
formater.numberStyle = .decimal
let formattedNumber = formater.string(from: number)

回答2:

You can do it with NumberFormatter:

let yourNumber = 123234234234 
let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = NumberFormatter.Style.decimal
numberFormatter.groupingSeparator = "."
let formattedNumber = numberFormatter.string(from: NSNumber(value:yourNumber))

回答3:

Details

Xcode 9.2, Swift 4
Xcode 10.2 (10E125), Swift 5

Solution

import Foundation

extension String { var toLocale: Locale { return Locale(identifier: self) } }

extension NumberFormatter {
    convenience init(numberStyle: NumberFormatter.Style, groupingSeparator: String?, decimalSeparator: String?) {
        self.init()
        set(numberStyle: numberStyle, groupingSeparator: groupingSeparator, decimalSeparator: decimalSeparator)
    }

    convenience init(numberStyle: NumberFormatter.Style, locale: Locale) {
        self.init()
        set(numberStyle: numberStyle, locale: locale)
    }

    func set(numberStyle: NumberFormatter.Style, groupingSeparator: String?, decimalSeparator: String?) {
        self.locale = nil
        self.numberStyle = numberStyle
        self.groupingSeparator = groupingSeparator
        self.decimalSeparator = decimalSeparator
    }

    func set(numberStyle: NumberFormatter.Style, locale: Locale?) {
        self.numberStyle = numberStyle
        self.locale = locale
    }
}

extension Numeric {
    func format(formatter: NumberFormatter) -> String? {
        if let num = self as? NSNumber { return formatter.string(from: num) }
        return nil
    }
}

Usage

let formatter = NumberFormatter(numberStyle: .decimal, locale: "fr_FR".toLocale)
print(value.format(formatter: formatter))

formatter.set(numberStyle: .decimal, groupingSeparator: " ", decimalSeparator: ".")
print(value.format(formatter: formatter))

Full sample

Do not forget to add the solution code here

func test<T: Numeric>(value: T) {
    print("=========================================================")
    print("\(T.self), value = \(value)")

    let formatter = NumberFormatter(numberStyle: .decimal, locale: "fr_FR".toLocale)
    print(value.format(formatter: formatter) ?? "nil")
    formatter.set(numberStyle: .currency, locale: "de_DE".toLocale)
    print(value.format(formatter: formatter)  ?? "nil")
    formatter.set(numberStyle: .decimal, groupingSeparator: " ", decimalSeparator: ".")
    print(value.format(formatter: formatter)  ?? "nil")
}

func print(title: String, value: String?) {
    if let value = value { print("\(title) \(value)") }
}

test(value: Int(10000))
test(value: Double(10000.231))
test(value: Float(10000.231))

Result

=========================================================
Int, value = 10000
10 000
10.000,00 €
10 000
=========================================================
Double, value = 10000.231
10 000,231
10.000,23 €
10 000.231
=========================================================
Float, value = 10000.231
10 000,231
10.000,23 €
10 000.231

回答4:

There's actually much easier solution (there is no need to create NumberFormatter instance) and it takes into account the user's language:

let result = String(format: "%ld %@", locale: Locale.current, viewCount, "views")

Result for value 1000000 with English:

1,000,000

Russian:

1 000 000

p.s. in Android it's exactly the same String.format(Locale.getDefault(), "%,d %s", viewCount, "views")

回答5:

swift 4

extension Int {
    func formatnumber() -> String {
        let formater = NumberFormatter()
        formater.groupingSeparator = "."
        formater.numberStyle = .decimal
        return formater.string(from: NSNumber(value: self))!
    }
}

回答6:

For swift 4, I implemented an extension where I can choose the formatting or use default one if none is selected.

extension Int {
    func formatnumber(groupingSeparator: String?) -> String {
        let formater = NumberFormatter()
        formater.groupingSeparator = (groupingSeparator != nil) ? groupingSeparator! : ","
        formater.numberStyle = .decimal
        return formater.string(from: NSNumber(value: self))!
    }
}

回答7:

My script as an example:

1) Add extension to project

extension String {

    public func subString(startIndex: String.Index, endIndex: String.Index) -> String {
        return String(self[startIndex...endIndex])
    }

    public func subString(_ from: Int, _ to: Int) -> String {
          let startIndex = self.index(self.startIndex, offsetBy: from)
          let endIndex = self.index(self.startIndex, offsetBy: to)
        return String(self[startIndex...endIndex])
    }
}

2) Create file Utilites.swift and add my method

public func  priceNumFormat(_ number: String)->String{

    var formattedNumber = number
    var print = number
    var prefix = ""

    if number.range(of:"-") != nil {
        let index = number.index(of:"-")
        formattedNumber.remove(at: index ?? formattedNumber.endIndex)
        prefix = "-"
    }


    if formattedNumber.range(of:".") != nil {
        let index = formattedNumber.index(of:".")
        formattedNumber =  formattedNumber.subString(startIndex: formattedNumber.startIndex, endIndex: index ?? formattedNumber.endIndex)
        formattedNumber.remove(at: index ?? formattedNumber.endIndex)
    }

    if formattedNumber.count == 8 //10 000 000
    {
       let num0 = formattedNumber.subString(0, 1)
       let num1 = formattedNumber.subString(2, 4)
       let num2 = formattedNumber.subString(5, 7)
       print =  "\(num0) \(num1) \(num2)"
    }

    if formattedNumber.count == 7 //1 000 000
    {
        let num0 = formattedNumber.subString(0, 0)
        let num1 = formattedNumber.subString(1, 3)
        let num2 = formattedNumber.subString(4, 6)
        print =  "\(num0) \(num1) \(num2)"
    }

    if formattedNumber.count == 6 //100 000
    {
        let num0 = formattedNumber.subString(0, 2)
        let num1 = formattedNumber.subString(3, 5)
        print =  "\(num0) \(num1)"
    }

    if formattedNumber.count == 5 //10 000
    {
        let num0 = formattedNumber.subString(0, 1)
        let num1 = formattedNumber.subString(2, 4)
        print =  "\(num0) \(num1)"
    }

    if formattedNumber.count == 4 //1 000
    {
        let num0 = formattedNumber.subString(0, 0)
        let num1 = formattedNumber.subString(1, 3)
        print =  "\(num0) \(num1)"
    }

    if formattedNumber.count == 3 //100
    {
        print =  formattedNumber
    }

    if prefix.count > 0
    {
        print = "- \(print)"
    }

    return print;
}

3) Add code in your UIController

 let utils = Utilites()
            private func test(){
                var price =  self.utils.priceNumFormat("-12345678.000")
                print("\(price)") //-12 345 678
                price =  self.utils.priceNumFormat("-1234567.000")
                print("\(price)") //-1 234 567
                price =  self.utils.priceNumFormat("-123456.000")
                print("\(price)") //-123 456
                price =  self.utils.priceNumFormat("-12345.000")
                print("\(price)") //-12 345
                price =  self.utils.priceNumFormat("-1234.000")
                print("\(price)") //-1 234
                price =  self.utils.priceNumFormat("-123.000")
                print("\(price)") //-123

            }

来源：https://stackoverflow.com/questions/44630702/formatting-numbers-in-swift-3

标签

swift

numbers

nsnumberformatter