Distance Formatter for Swift

DistanceHelper.swift

//
//  DistanceHelper.Swift
//  Wildcard
//
//  Created by Samuel Beek on 01-05-15.
//  Copyright (c) 2015 Wildcard. All rights reserved.
//

import Foundation

extension String {
    mutating func deleteCharactersInRange(range: NSRange) {
        let startIndex = advance(self.startIndex, range.location)
        let length = range.length
        self.removeRange(Range<String.Index>(start: startIndex, end:advance(startIndex, length)))
    }
}

func formatDistance(meters: String) -> String {
    
    var distance = meters
    
    if(count(distance) > 3) {
        // remove last three characters and make it KM
        let index = count(distance)
        let start = index - 3
        distance.deleteCharactersInRange(NSMakeRange(start,3))
        return "\(distance)km"
        
    } else {
        // Deck is close, so use meters
        return "\(distance)m"
    }
}