Convert Distances in Swift using Measurement

ConvertDistances.md

Distance conversion in Swift

As of iOS 10, the Measurement class was introduced, which obviates the need lookup values and create constants to convert values. Here is a simple extension to convert distances.

extension Double {
  func convert(from originalUnit: UnitLength, to convertedUnit: UnitLength) -> Double {
    return Measurement(value: self, unit: originalUnit).converted(to: convertedUnit).value
  }
}

Usage

let miles = 1.0
let metersInAMile = miles.convert(from: .miles, to: .meters)

let mileInFeet = 5280.0
let feetInAMile = mileInFeet.convert(from: .feet, to: .miles)

let marathonInFeet = 138_435.0
let milesInMarathon = marathonInFeet.convert(from: .feet, to: .miles)
let kmInMarathon = marathonInFeet.convert(from: .feet, to: .kilometers)

let inch = 1.0
let centimetersInInch = inch.convert(from: .inches, to: .centimeters)