Swift function that returns a UIColor from a color in hexadecimal

ColorWithHexString.swift

func colorWithHexString (hex:String) -> UIColor {
    var cString:String = hex.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines).uppercased()
    if (cString.hasPrefix("#")) {
        let index = cString.index(cString.startIndex, offsetBy: 1)
        cString = cString.substring(from: index)
    }
    
    if (cString.characters.count != 6) {
        return UIColor.gray
    }
    
    var rgbValue:UInt32 = 0
    Scanner(string: cString).scanHexInt32(&rgbValue)
    
    return UIColor(
        red: CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0,
        green: CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0,
        blue: CGFloat(rgbValue & 0x0000FF) / 255.0,
        alpha: CGFloat(1.0)
    )
}

Bravo!