Loading files from a directory code challenge.

TL;DR: pathForResource:ofType: returns an optional, and you need to unwrap it.

The problem here lies in Swift's love of over-safety. It has a concept of "Optionals", where a variable could either contain a value or nil. To find out, you have to "unwrap" it. This could be done in one of two ways.

The Easy Way

The fastest is to explicitly unwrap it is inline with an exclamation point. Be careful, though, as if it actually does contain nil, your app will crash. It's probably ok in this case, since it should never be nil, but you should form a habit of using the other way, which I'll show you in a second. In the meantime, explicitly unwrapping it would make your code look like this:

// This constant is inferred to be a String? (an optional String)
let plistPath = NSBundle.mainBundle().pathForResource("CrazyInformation", ofType: "plist")
// Notice the ! after plistPath. This unwraps the optional to get to the value inside
let dictionary = NSDictionary(contentsOfFile: plistPath!)

The Better Way

There's a better way to do this, though. That would be to implicitly unwrap it, which is known as "if let" syntax. This is better because it's safer. If the value contains nil, your app won't crash, and you can run some alternate code, instead. Using if let syntax extracts the value out of the optional and assigns it to its own temporary constant which is only available within the scope of the if let statement. Implicitly unwrapping it would look like this:

// This constant is inferred to be a String? (an optional String)
let plistPath = NSBundle.mainBundle().pathForResource("CrazyInformation", ofType: "plist")
// This will extract the String value from the optional and assign it to path
if let path = plistPath{
    let dictionary = NSDictionary(contentsOfFile: path)
}