Question: What Is Difference Between If Let And Guard In Swift?

What is difference between guard and if let?

guard let will unwrap an optional for you, but if it finds nil inside it expects you to exit the function, loop, or condition you used it in.

However, the major difference between if let and guard let is that your unwrapped optional remains usable after the guard code..

How do you use Guard?

The main use of guard statement is to transfer program control out of a scope on certain conditions. These statements are similar with if statements which executes statements based on certain condition (boolean value) but unlike if, the guard statements only run when certain conditions are not met.

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 .

How do I check if a swift Keyal is empty?

You can use an if statement to find out whether an optional contains a value. If an optional does have a value, it evaluates to true; if it has no value at all, it evaluates to false. and if you are using the xyz in if statement. Than you can unwrap xyz in if statement in constant variable .

Do try catch Swift?

The try/catch syntax was added in Swift 2.0 to make exception handling clearer and safer. It’s made up of three parts: do starts a block of code that might fail, catch is where execution gets transferred if any errors occur, and any function calls that might fail need to be called using try .

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.

What is guard let in Swift?

Swift gives us an alternative to if let called guard let , which also unwraps optionals if they contain a value, but works slightly differently: guard let is designed to exit the current function, loop, or condition if the check fails, so any values you unwrap using it will stay around after the check.

What does if let mean in Swift?

The “if let” allows us to unwrap optional values safely only when there is a value, and if not, the code block will not run. Simply put, its focus is on the “true” condition when a value exists.

What is unwrapping 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.

Why optionals are useful 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.

What is bundle in iOS Mcq?

In iOS, a folder with . app extension is known as Bundle.

What is optionals in 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. … Optionals are similar to using nil with pointers in Objective-C, but they work for any type, not just classes.

What is closure in Swift?

Closures are self-contained blocks of functionality that can be passed around and used in your code. Closures in Swift are similar to blocks in C and Objective-C and to lambdas in other programming languages. … Nested functions are closures that have a name and can capture values from their enclosing function.

What is a bundle in iOS?

A bundle is a directory in the file system that groups executable code and related resources such as images and sounds together in one place. In iOS and OS X, applications, frameworks, plug-ins, and other types of software are bundles.

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.