FloatValue，带有来自textField的2位小数 [英] FloatValue with 2 decimals from textField

问题描述

在我的核心数据应用程序中，我从3个UITexFields中保存了3个浮点数。要做到这一点，我必须将它们转换为字符串。

In my Core Data app I save 3 Floating point numbers from 3 UITexFields. To do that I had to convert them to Strings.

现在的问题是值被舍入到 .0 。

Now the problem is that the values are rounded to .0.

我该怎么做？

nyTankning.liter = (textFieldLiter.text as NSString).floatValue
nyTankning.kronor = (textFieldKronor.text as NSString).floatValue
nyTankning.literpris = (textFieldLiterpris.text as NSString).floatValue 

推荐答案

你的问题是你试图使用逗号，代替句点。

Your problem there is that you are trying to use a comma "," instead of a period "."

extension String {
    var converted: String {
        return fractionDigits()
    }
    var toDouble: Double {
        return NSNumberFormatter().numberFromString(self)!.doubleValue
    }
    var toFloat: Float {
        return NSNumberFormatter().numberFromString(self)!.floatValue
    }
    func fractionDigits(min:Int = 2, max:Int = 2)-> String {
        let styler = NSNumberFormatter()
        styler.minimumFractionDigits = min
        styler.maximumFractionDigits = max
        let converter = NSNumberFormatter()
        converter.decimalSeparator = "."
        if let result = converter.numberFromString(self) {
            return styler.stringFromNumber(result)!
        } else {
            converter.decimalSeparator = ","
            if let result = converter.numberFromString(self) {
                return styler.stringFromNumber(result)!
            }
        }
        return ""
    }
}
"1,1222".converted           // "1.12"
"2".converted                // "2.00"

"1,1222".converted.toDouble  // 1.12
"2".converted.toDouble       // 2.0

"1,1222".converted.toFloat   // 1.12000000476837
"2".converted.toFloat        // 2.0

"1.1222".converted           // "1.12"
"1.1222".converted.toDouble  // 1.12
"1.254".converted.toFloat    // 1.25

"1.254".fractionDigits(min: 1, max: 2) // "1.25"
"1.2".fractionDigits(min: 1, max: 2)   // "1.2"

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