Format Double or Float values without rounded. Use this method and set maximum decimals according to your need.

IWADecimalFormat

func IWADoubleFormat(_ a: Double, max: Int) -> Double {
        let stringArr = String(a).split(separator: ".")
        let decimals = Array(stringArr[1])
        var string = "\(stringArr[0])."

        var count = 0;
        for n in decimals {
            if count == max { break }
            string += "\(n)"
            count += 1
        }


        let double = Double(string)!
        return double
    }