What is else if in Swift?

What is else if in Swift?

Swift if…else Statement

An if statement can have an optional else clause. The if…else statement evaluates the condition inside the parenthesis. If the condition evaluates to true, the code inside if is executed.

What does == mean in Swift?

double-equals operator
== Operator in Swift. The double-equals operator (==) in Swift is used to check if two values are equal. For example: let num1 = 2. let num2 = 2.

What is #if in Swift?

Replies. It is correct that Swift doesn’t have a preprocessor. But it is clearly documented the condition of #if/#endif is evaluated at compile time and the code block is conditionallly compiled.

What does the targetEnvironment () compiler condition do?

The targetEnvironment() platform condition returns true when code is being compiled for the specified environment; otherwise, it returns false .

What is lazy in Swift?

A lazy stored property is a property whose initial value isn’t calculated until the first time it’s used. You indicate a lazy stored property by writing the lazy modifier before its declaration.

What is defer in iOS?

The defer statement will keep your iOS application code running smoothly, even if a team member updates a method or adds a conditional statement. defer executes no matter how we exit and future proofs projects from changes that may alter the scope flow, reducing the possibility of an error.

What is -= in Swift?

-= Subtract AND assignment operator, It subtracts right operand from the left operand and assigns the result to left operand. C -= A is equivalent to C = C – A. *= Multiply AND assignment operator, It multiplies right operand with the left operand and assigns the result to left operand.

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.

What is debugPrint in Swift?

debugPrint() – Writes the textual representations of the given items most suitable for debugging into the standard output. Basically debugPrint adds additional information that is useful for debugging like type information etc.

Why we use defer in Swift?

The Swift defer statement is useful for cases where we need something done — no matter what — before exiting the scope. For example, defer can be handy when cleanup actions are performed multiple times, like closing a file or locking a lock, before exiting the scope.

What does the canImport () compiler condition do?

Suggested approach: You should get straight to the point and say that canImport() returns true if a module such as UIKit can be imported, then provide a practical example such as it allowing us to write code that does one thing using UIKit on iOS, and another thing using AppKit on macOS.

What is singleton in Swift?

In Swift, Singleton is a design pattern that ensures a class can have only one object. Such a class is called singleton class. To create a singleton class, we need to follow some rule. 1. Create a private initializer.

What is a weak VAR in Swift?

Weak References in Swift
Weak References are one solution to retain cycles in Swift. A weak reference does not increment or decrement the reference count of an object. Since weak references do not increment the reference count of an object, a weak reference can be nil .

Is defer called after return Swift?

By using defer in Swift you can execute important logic after the return, defer logic, and defer completion callbacks to ensure completion blocks are called.

What is data type in Swift?

Swift Data Types

Why is Swift safer?

Another safety feature is that by default Swift objects can never be nil. In fact, the Swift compiler will stop you from trying to make or use a nil object with a compile-time error. This makes writing code much cleaner and safer, and prevents a huge category of runtime crashes in your apps.

What is double Swift?

Swift version: 5.6. Paul Hudson @twostraws March 16th 2020. The Double data type is the standard Swift way of storing decimal numbers such as 3.1, 3.14159 and 16777216.333921.

What is difference between print and debugPrint?

print() – Writes the textual representations of the given items into the standard output. debugPrint() – Writes the textual representations of the given items most suitable for debugging into the standard output. Basically debugPrint adds additional information that is useful for debugging like type information etc.

What is dump in Swift?

Dumps the given object’s contents using its mirror to standard output and specified output stream. We can use also Dump for the same purpose as we used to print() but print() only prints the class name while in the case of dump() prints the whole class hierarchy at Xcode debug console.

What are active compilation conditions?

The new setting is called “Active Compilation Conditions”, which provides top-level support for the Swift equivalent of preprocessor flags. You use it in exactly the same way as you would “Other Swift Flags”, except there’s no need to prepend the value with a “-D” (so it’s just a little cleaner).

How do I use another Swift flag?

To do that, goto Project (not target)→Build settings → Swift Compiler → Custom flags → Other swift flags section and edit the different configuration flags. Add the flags using the syntax “ -D <flag_name>”. NOTE: if you are not seeing Other swift flags section, you will be in the basic build settings mode.

What is a lazy VAR in Swift?

A lazy var is a property whose initial value is not calculated until the first time it’s called. It’s part of a family of properties in which we have constant properties, computed properties, and mutable properties.

What is private init in Swift?

The default memberwise initializer for a structure type is considered private if any of the structure’s stored properties are private. Likewise, if any of the structure’s stored properties are file private, the initializer is file private. Otherwise, the initializer has an access level of internal.

How do I stop retaining cycles in Swift?

For example; when we set mercedes instance to nil , the compiler cannot decrease its ARC to 1 because a Car object is still referencing the mercedes and vice versa. In order to prevent this retain cycle, we need to declare at least one of the variable as weak or unowned.

Why defer is used in Swift?