How do you fix unexpectedly found nil while unwrapping an optional value?

How do you fix unexpectedly found nil while unwrapping an optional value?

99% of the time the above error is caused by a force-unwrapped optional that is nil . You can fix it by avoiding it becomes nil , which is sometimes not possible, so then you use optional binding or optional chaining. Avoid using implicitly unwrapped optionals when you can, unless you have a specific need to use it.

How do I unwrap optional in Swift?

You can force unwrap an optional by adding an exclamation mark after the optional constant or variable, like this: print(email!) Now, consider the following two scenarios: Instead of having a value, email is nil .

What is swift optional?

An optional in Swift is basically a constant or variable that can hold a value OR no value. The value can or cannot be nil. It is denoted by appending a “?” after the type declaration. This is a big impact on the language Swift itself because what that means is that anything non-optional types can never be nil.

What is unwrapped in Swift?

Unwrapping an optional means that you are now casting that type as non-optional. This will generate a new type and assign the value that resided within that optional to the new non-optional type. This way you can perform operations on that variable as it has been guaranteed by the compiler to have a solid value.

What is the difference between if let and guard let in Swift?

In if let , the defined let variables are available within the scope of that if condition but not in else condition or even below that. In guard let , the defined let variables are not available in the else condition but after that, it’s available throughout till the function ends or anything.

What happens if you unwrap a non existent optional value?

Please remember that if you force unwrap a nil value, your code will crash. Example, Double(“3”), here “3” can be converted into Double , so it returns an optional Double value corresponding to 3. Double(“abc”), here “abc” cannot be converted into Double , so it returns nil in this case.

What does fatal error unexpectedly found nil while?

Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value. In order to work out which variable caused the crash, you can hold ⌥ while clicking to show the definition, where you might find the optional type. IBOutlets, in particular, are usually implicitly unwrapped optionals.

What is the fatal error of implicit unwrapping?

Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value This crash arises when we attempt to forcefully or Implicitly unwrap an optional and that optional, as the name suggests, does not contain any value.

When is an optional value is nil in Swift?

In Swift, an optional can either have an ordinary value, or be nil. When a variable has no value it is nil. Almost every programming language has something similar to nil. It’s undefined in JavaScript, null in Java and NULL in PHP.

When do optional values have to be unwrapped?

An optional value must be unwrapped before it can be used. Optional is a generic type, which means that Optional and Optional are distinct types — the type inside <> is called the Wrapped type. Under the hood, an Optional is an enum with two cases: .some (Wrapped) and .none, where .none is equivalent to nil.