How to truncate decimals to x places in Swift

Question

In my swift program, I have a really long decimal number (say 17.9384693864596069567) and I want to truncate the decimal to a few decimal places (so I want the

Answer 1

extension Double {
    /// Rounds the double to decimal places value
    func roundToPlaces(_ places:Int) -> Double {
        let divisor = pow(10.0, Double(places))
        return (self * divisor).rounded() / divisor
    }
    func cutOffDecimalsAfter(_ places:Int) -> Double {
        let divisor = pow(10.0, Double(places))
        return (self*divisor).rounded(.towardZero) / divisor
    }
}

let a:Double = 1.228923598

print(a.roundToPlaces(2)) // 1.23
print(a.cutOffDecimalsAfter(2)) // 1.22