What is optional in IOS Swift?

An Optional is a type on its own, actually one of Swift 4’s new super-powered enums. It has two possible values, None and Some(T), where T is an associated value of the correct data type available in Swift 4.

How do I make Swift optional?

To use an optional, you “unwrap” it The simplest way to unwrap an optional is to add a ! after the optional name. This is called “force unwrapping”. It returns the value inside the optional (as the original type) but if the optional is nil , it causes a runtime crash.

How do I unwrap optional in Swift?

Unwrap an optional type with optional binding Then in the if-let block, the optional value password is unwrapped and assigned to the variable unwrappedpass only if the optional value password is not nil. unwrappedpass now contains the unwrapped value and can be used within the block’s scope.

Why do we need optionals in Swift?

Optionals are in the core of Swift and exist since the first version of Swift. An optional value allows us to write clean code with at the same time taking care of possible nil values. If you’re new to Swift you might need to get used to the syntax of adding a question mark to properties.

Is optional an enum?

Basically, an Optional is an Enum with 2 cases and one of the cases has an associated value attached to it. That’s it! This is all the magic behind that mysterious thing called Optional. An Optional is just a value wrapper.

How does Swift handle optional values?

Optional Handling

  1. If-statement. You can use if statement and compare optional with nil to find out whether a optional contains a value or not.
  2. Optional Binding (if-let) Optional binding helps you to find out whether an optional contains a value or not.
  3. Guard statement.
  4. Nil-coalescing operator.

What is optional value in Swift?

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.

How do I unpack optional?

A common way of unwrapping optionals is with if let syntax, which unwraps with a condition. If there was a value inside the optional then you can use it, but if there wasn’t the condition fails. For example: if let unwrapped = name { print(“\(unwrapped.

What is implicitly unwrapped optional?

You could see an implicitly unwrapped optional as an optional whose value is always accessed by forced unwrapping. This also means that a runtime error is thrown if you access an implicitly unwrapped optional that has no value.

What is the difference between optional none and nil?

Answer : There is no difference. Optional. None (. None for short) is the correct way of initializing an optional variable lacking a value, whereas nil is just syntactic sugar for .

What is enum in Swift?

In Swift, an enum (short for enumeration) is a user-defined data type that has a fixed set of related values. We use the enum keyword to create an enum. For example, enum Season { case spring, summer, autumn, winter } Here, Season – name of the enum.

Is optional nil by default?

Yes it is automatically set to nil if unassigned.