How to represent magnitude for mass in Swift?

Question

// SI units
enum Magnitude : Measurement {
    case Milli = Measurement(-3, \"ml\")
    case Centi = Measurement(-2, \"cl\")
    case Desi = Measurement(-1, \"dl\")
         


        

Answer 1

Did you consider using a dictionary? For example:

let magnitudes: [String: Double] = [
    "ml": -3,
    "cl": -2,
    "dl": -1,
    "g": 0,
    "kg": 3

]

// list all units:
println(", ".join(magnitudes.keys)) // kg, g, ml, cl, dl


// convert
func convert(from: String, to: String, value: Double) -> Double{
    let mag1 = __exp10(magnitudes[from]!)
    let mag2 = __exp10(magnitudes[to]!)
    return value * mag1 / mag2
}


let result = convert("dl", "ml", 3.0)
println(result) // 300.0