What Is The Difference Between Weak And Unowned?

What is the difference between weak and strong?

A variable that does not take ownership of an object is known as a weak reference.

strong is the default.

An object remains “alive” as long as there is a strong pointer to it.

A weak reference is set to nil when there are no strong references to the object..

Why is IBOutlet weak?

In Mac development an IBOutlet is usually a weak reference: if you have a subclass of NSViewController only the top-level view will be retained and when you dealloc the controller all its subviews and outlets are freed automatically. UiViewController use Key Value Coding to set the outlets using strong references.

What is a lazy VAR in Swift?

Swift has a mechanism built right into the language that enables just-in-time calculation of expensive work, and it is called a lazy variable. These variables are created using a function you specify only when that variable is first requested.

Why is delegate weak in iOS?

For delegation patters in iOS, the delegated object is the parent, because there is no need for the delegate caller to exist without the delegated object. … When you define a delegate object as property, it’s used a weak reference in the object it is defined in(lets say A, i.e. the delegate object is a property of A).

What is weak acid?

Weak Acids are the acids that do not completely dissociate into their constituent ions when dissolved in solutions. When dissolved in water, an equilibrium is established between the concentration of the weak acid and its constituent ions.

What is difference between weak and strong in Swift?

A strong reference means that you want to “own” the object you are referencing with this property/variable. In contrast, with a weak reference you signify that you don’t want to have control over the object’s lifetime. A weak reference is like observing the tree from afar. …

What is strong what is weak why we want to use unowned and weak self?

In Swift, we need to use weak self and unowned self to give ARC the required information between relationships in our code. Without using weak or unowned you’re basically telling ARC that a certain “strong reference” is needed and you’re preventing the reference count from going to zero.

What is unowned self in Swift?

The most common place you’ll see unowned variables is with closures that declare [unowned self] – this means “I want to reference self inside this closure but I don’t want to own it.” Why unowned rather than weak ? Both would work, but let’s face it: if self is nil inside a closure, something has gone wrong!

Is Siri weak AI?

Siri, Cortana, and Google Assistant are all examples of narrow AI, but they are not good examples of a weak AI, as they operate within a limited pre-defined range of functions. … They are in particular not examples of strong AI as there are no genuine intelligence nor self-awareness.

What is weak in Swift?

A weak reference is just a pointer to an object that doesn’t protect the object from being deallocated by ARC. In Swift, all weak references are non-constant Optionals (think var vs. … let ) because the reference can and will be mutated to nil when there is no longer anything holding a strong reference to it.

Why do you generally create a weak reference when using self in a block?

You don’t have to always use a weak reference. If your block is not retained, but executed and then discarded, you can capture self strongly, as it will not create a retain cycle. In some cases, you even want the block to hold the self until the completion of the block so it does not deallocate prematurely.

Is Alexa weak AI?

Siri and Alexa could be considered AI, but generally, they are weak AI programs. Even advanced chess programs are considered weak AI.