Quick Answer: What Is Difference Between Any And AnyObject In Swift?

What is enum in Swift?

An enumeration defines a common type for a group of related values and enables you to work with those values in a type-safe way within your code.

Enumerations in Swift are first-class types in their own right.

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What is Self in Swift?

In Swift self is a special property of an instance that holds the instance itself. Most of the times self appears in an initializer or method of a class, structure or enumeration. … Or accessing the property from a method brings sufficient context to omit self from self.

How many protocols can a swift class adopt?

Since classes, structures and, enums can conform to more than one protocol, they can take the default implementation of multiple protocols. This is conceptually similar to multiple inheritance in other languages.

What is NSArray?

NSArray is Objective-C’s general-purpose array type. It represents an ordered collection of objects. NSArray is immutable, so we cannot dynamically add or remove items. Its mutable counterpart, NSMutableArray, will be discussed in the second part of this tutorial.

Why struct is faster than Class Swift?

So based on the above theory we can say that Struct is faster than Class because: To store class, Apple first finds memory in Heap, then maintain the extra field for RETAIN count. Also, store reference of Heap into Stack. So when it comes to access part, it has to process stack and heap.

Is kind of class in Swift?

Unlike other programming languages, Swift doesn’t require you to create separate interface and implementation files for custom structures and classes. In Swift, you define a structure or class in a single file, and the external interface to that class or structure is automatically made available for other code to use.

What is type in Swift?

In Swift, there are two kinds of types: named types and compound types. A named type is a type that can be given a particular name when it’s defined. Named types include classes, structures, enumerations, and protocols. … A compound type is a type without a name, defined in the Swift language itself.

Should I use struct or class Swift?

Use classes if you want reference types. Use structs if you want value types. Even though struct and enum don’t support inheritance, they are great for protocol-oriented programming. A subclass inherits all the required and unwanted functionalities from the superclass and is a bad programming practice.

Is Swift type safe?

Swift is a type-safe language. A type safe language encourages you to be clear about the types of values your code can work with. If part of your code requires a String , you can’t pass it an Int by mistake. … If you don’t specify the type of value you need, Swift uses type inference to work out the appropriate type.

Is keyword in Swift?

As far as I can look, it seems that the consensus is that the is in Swift keyword is synonymous to isKindOfClass method. When this block of code was called, I made sure I was in my ActivityViewController tab. isKindOfClass was correct, selectedViewController is ActivityViewController was not.

Is Swift similar to Python?

Swift is more similar to languages such as Ruby and Python than is Objective-C. For example, it’s not necessary to end statements with a semicolon in Swift, just like in Python. … If you cut your programming teeth on Ruby and Python, Swift should appeal to you.

Should I use struct or class C++?

use struct for plain-old-data structures without any class-like features; use class when you make use of features such as private or protected members, non-default constructors and operators, etc.

What is difference between NSArray and NSMutableArray?

The primary difference between NSArray and NSMutableArray is that a mutable array can be changed/modified after it has been allocated and initialized, whereas an immutable array, NSArray , cannot. … This syntax creates an instance of an array for us.

What is Downcasting in Swift?

Type casting is a way to check the type of an instance, or to treat that instance as a different superclass or subclass from somewhere else in its own class hierarchy. Type casting in Swift is implemented with the is and as operators.

What is the difference between class and structure in Swift?

Classes and structs in Swift are basic constructs of your program. In Swift, both classes and structs can have properties and functions. The key difference is structs are value types and classes are reference types. Because of this, let and var behave differently with structs and classes.

Is Vs as Swift?

Type casting in Swift is implemented with the is and as operators. is is used to check the type of a value whereas as is used to cast a value to a different type. … In order to work with them as their native type, you need to check their type, or downcast them to a different type.

Is Swift an operator?

As operator is used to convert one type to another when compiler is guaranteeing the success of desired cast. … as is an old operator. This can be used to convert primitive types which are interchangeable or converting Swift types to Objective-C and vice versa.

What is difference between Array and NSArray in Swift?

Array is a struct, therefore it is a value type in Swift. NSArray is an immutable Objective C class, therefore it is a reference type in Swift and it is bridged to Array . NSMutableArray is the mutable subclass of NSArray . … It will also work if you do let arr instead of var as with other reference types.

Where is Swift used?

Swift is a compiled programming language for iOS, macOS, watchOS, tvOS, and Linux applications. Here’s what you need to know about Swift. Created by Apple in 2014. Backed up by one of the most influential tech companies in the world, Swift is set to become the dominant language for iOS development and beyond.

Can structs have methods?

Contrary to what younger developers, or people coming from C believe at first, a struct can have constructors, methods (even virtual ones), public, private and protected members, use inheritance, be templated… just like a class .

What is higher order functions in Swift?

Higher order functions are simply functions that operate on other functions by either taking a function as an argument, or returning a function . Swift’s Array type has a few methods that are higher order functions: sorted, map, filter, and reduce.