regex vs double for isNumeric

isnumeric.playground

//: Playground - noun: a place where people can play

import UIKit

var timeDiff: Double = 0

public extension String {
    public var isNumericRegex: Bool {
        return range(of: "(^-?[\\d]+$)|(-?[\\d]+[.,]{1}[\\d]+$)",
                     options: String.CompareOptions.regularExpression, range: nil, locale: nil) != nil
    }
    
    public var isNumericDouble: Bool {
        return  Double(self) != nil
    }
    
    public static func loremIpsum(ofLength length: Int = 445) -> String {
        guard length > 0 else { return "" }
        
        // https://www.lipsum.com/
        let loremIpsum = """
        Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
        """
        if loremIpsum.count > length {
            return String(loremIpsum[loremIpsum.startIndex..<loremIpsum.index(loremIpsum.startIndex, offsetBy: length)])
        }
        return loremIpsum
    }
}

func usingRegex(num: String) -> Double {
    let start = DispatchTime.now()
    if num.isNumericRegex == false {
    }
    let end = DispatchTime.now()
    let nanoTime = end.uptimeNanoseconds - start.uptimeNanoseconds // <<<<< Difference in nano seconds (UInt64)
    let timeInterval = Double(nanoTime) / 1_000_000_000 // Technically could overflow for long running tests

    return timeInterval
}

func usingDouble(num: String) -> Double {
    let start = DispatchTime.now()
    if num.isNumericDouble == false {
    }
    let end = DispatchTime.now()
    let nanoTime = end.uptimeNanoseconds - start.uptimeNanoseconds // <<<<< Difference in nano seconds (UInt64)
    let timeInterval = Double(nanoTime) / 1_000_000_000 // Technically could overflow for long running tests
    
    return timeInterval
}

for _ in 1...10000 {
//    let diceRoll = String(Int(arc4random_uniform(600000)))
    let diceRoll = String.loremIpsum()
    timeDiff += (usingRegex(num: diceRoll) - usingDouble(num: diceRoll))
}


print("Regex is slower by: \(timeDiff) seconds")