Making life easier - Swift "Tweaks"

What I really like about programing is the idea of reusability. The fact that you can use a chunk of code today for one project and then again the following year for a different project is remarkably satisfying. Learning Swift these days gives us, iOS programers, a great opportunity to re-think our old manners, code snippets and techniques. We can create new ones from scratch and use all we’ve learned over the years to make them even more clever.

Let me show you a bunch of Swift functions and extensions I’m using. Don’t expect any new, rule-breaking ideas, though. These are common and well-known things. Or at least (I think) they should be.

func RGB(red: CGFloat, green: CGFloat, blue: CGFloat) -> UIColor! {
    return RGBA(red, green, blue, 1)

func RGBA(red: CGFloat, green: CGFloat, blue: CGFloat, alpha: CGFloat) -> UIColor! {
    return UIColor(red: red/255.0, green: green/255.0, blue: blue/255.0, alpha: alpha)
func delay(delay:Double, closure:  ()->()) {
            Int64(delay * Double(NSEC_PER_SEC))

        dispatch_get_main_queue(), closure)

EDIT: Repeat became a keyword in Swift 2.0 so this is no longer a valid code

// example:

repeat(100) {    
    println("I will not record vertical oriented videos. \n")

func repeat(cycles: Int, closure: () -> ()) {
    for _ in 0..<cycles {
func printAllAvailableFonts() {
    let fontFamilyNames = UIFont.familyNames()

    for familyName in fontFamilyNames {        
        println("Font Family Name = [\(familyName)]")
        let names = UIFont.fontNamesForFamilyName(familyName as! String)
        println("Font Names = [\(names)]")

Note: This function needs String subscript extension you can find below.

func randomStringWithLength (length : Int) -> String {
    let letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
    var randomString = ""
    repeat(length) {
        let rand = Int(arc4random_uniform(UInt32(count(letters))))

    return randomString
extension String {
    subscript (i: Int) -> Character {
        return self[advance(self.startIndex, i)]
    subscript (i: Int) -> String {
        return String(self[i] as Character)
    subscript (r: Range<Int>) -> String {
        return substringWithRange(Range(start: advance(startIndex, r.startIndex), end: advance(startIndex, r.endIndex)))
func between<T : Comparable>(minimum: T, maximum: T, value: T) -> T {
    return min( max(minimum, value) , maximum)
extension UITableViewCell {
    class func reusableIdentifier() -> String! {
        return NSStringFromClass(self) + "Identifier"

extension UICollectionViewCell {
    class func reusableIdentifier() -> String! {
        return NSStringFromClass(self) + "Identifier"
extension UIImage {	
    func imageWithColor(color: UIColor) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(self.size, false, self.scale)

        let context = UIGraphicsGetCurrentContext()
        CGContextTranslateCTM(context, 0, self.size.height)
        CGContextScaleCTM(context, 1.0, -1.0)
        CGContextSetBlendMode(context, kCGBlendModeNormal)

        let rect = CGRectMake(0, 0, self.size.width, self.size.height)
        CGContextClipToMask(context, rect, self.CGImage)
        CGContextFillRect(context, rect)

        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        return newImage;

You can find all the Swift “tweaks” I’m using in my projects on my GitHub - iOS-SwiftTweaks. I’d love to hear about your tweaks!