迅捷-删除双精度的尾随零 [英] Swift - Remove Trailing Zeros From Double

问题描述

从双精度中删除尾随零的功能是什么?

What is the function that removes trailing zeros from doubles?

var double = 3.0
var double2 = 3.10

println(func(double)) // 3
println(func(double2)) // 3.1

推荐答案

在Swift 4中，您可以这样做:

In Swift 4 you can do it like that:

extension Double {
    func removeZerosFromEnd() -> String {
        let formatter = NumberFormatter()
        let number = NSNumber(value: self)
        formatter.minimumFractionDigits = 0
        formatter.maximumFractionDigits = 16 //maximum digits in Double after dot (maximum precision)
        return String(formatter.string(from: number) ?? "")
    }
}

使用示例:print (Double("128834.567891000").removeZerosFromEnd()) 结果:128834.567891

example of use: print (Double("128834.567891000").removeZerosFromEnd()) result: 128834.567891

您还可以计算字符串中有多少个十进制数字:

You can also count how many decimal digits has your string:

import Foundation

extension Double {
    func removeZerosFromEnd() -> String {
        let formatter = NumberFormatter()
        let number = NSNumber(value: self)
        formatter.minimumFractionDigits = 0
        formatter.maximumFractionDigits = (self.components(separatedBy: ".").last)!.count
        return String(formatter.string(from: number) ?? "")
    }
}

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