Unwrapping an optional means that you are now casting that type as non-optional. They are two different types that can not be operated on each other. Of course, like any if statement, you may include an else block. Heck, even if you’re 99.999% certain that it’s safe, you shouldn’t be using it – that equates to one crash in 100,000, which is really bad. Hopefully you can see the difference between the two: one situation is guaranteed to work 100% of the time, and the other “should” work or “will nearly always work”. Hmm. For a discussing on avoiding force unwrapping, check out this blog post from Alexandre Colucci: https://blog.timac.org/2017/0628-swift-banning-force-unwrapping-optionals/. This is ok as long as the variable indeed is of the type you are casting it to, otherwise you'll have a mess on your hands. In other words, you have to assign a non-nil value to the variable. Join Stack Overflow to learn, share knowledge, and build your career. Both usernameField and its text property are optionals, so we’ll need to unwrap the optional to get to the value. E.g. When is it useful? Same with Swift. would result in a having type Optional, and declarations like var b: String! That is why dealing with collection types (Dictionaries and Arrays) in Swift can get kind of hairy. The first way to unwrap an optional in Swift is something called force unwrapping. And finally, we bind it to the view model's variable. Great explanation. Sponsor Hacking with Swift and reach the world's largest Swift community! if let unwrapped = name { print("\ (unwrapped.count) letters") } else { print("Missing name.") Because Swift provides several ways to safely unwrap optional values, you can choose the one that helps you write clear, concise code. That’s it – that’s the entire rule. Optional Binding is a mess topic to understand, but you can! I'm learning Swift for iOS 8 / OSX 10.10 by following this tutorial, and the term "unwrapped value" is used several times, as in this paragraph (under Objects and Class): When working with optional values, you can write ? You can declare optional variables using exclamation mark instead of a question mark. Swift : Unwrapping Like a Boss. This is dangerous for several reasons. Here is a good analogy that helped me a lot. In fact, whenever you attempt to. However, I am not advocating that you start scattering exclamation marks around your program, because that starts to get messy. symbol. If there is something inside, it could be yet another present, which is also wrapped, and which also might contain nothing. You might know the type of the something. That might save you a line or two of code, but “that should never crash” isn’t a good enough reason for a force unwrap, and we can all do better. Such optional variables will unwrap automatically and you do not need to use any further exclamation mark at the end of the variable to get the assigned value. The following examples use this dictionary of image names and file paths: How do I unwrap an Optional when pattern matching tuples in Swift? First, you have to understand what an Optional type is. Then, we'll use unwrap functions since the text variable is an optional (to make sure it actually contains a value). But if you declare a value as implicitly unwrapped, it is equivalent to force unwrapping it at every use. That’s the key here: you should never force unwrap something that won’t succeed 100% of the time. You can use a conditional check on an optional to execute some code only if the optional type holds a value. https://learnappmaking.com/found-nil-while-unwrapping-optional-value The techniques discussed in this case “ moo ” ) without unwrapping it generate! 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