Apple’s Swift programming language: Cheat sheet

Apple’s Swift has far-reaching results on all platforms, not simply iOS, OS X, watchOS and tvOS. Study why Swift issues, find out how to use the programming language and the way it differs from Goal-C.

Goal-C has received the hearts of many builders. It began as a programming language that bundled object-oriented programming (OOP) with the likeness of the C programming language. Goal-C known as NeXT and Apple house the place it was the default programming language for NeXTSTEP, OS X and iOS.

In 2010, Apple began creating Swift, a brand new programming language that may rival Goal-C in a couple of areas–specifically, kind security, safety, and higher on-hardware efficiency. Swift is greater than 2.6x sooner than Goal-C and greater than 8.4x sooner than Python. Swift 1.0 was launched in September 2014.

SEE: Apple’s Swift programming language: Cheat sheet (free PDF) (TechRepublic)

Government abstract

  • What’s Apple’s Swift? Swift is the latest programming language from Apple; it gives higher kind security, safety and efficiency. Swift is accessible for creating iOS, OS X, watchOS and tvOS apps.
  • Why does Apple’s Swift matter? It is a straightforward programming language to study, which is why many college students, entry-level builders and long-standing Mac and iOS builders are focusing their growth abilities on Swift. As well as, Apple open sourced Swift, making it out there for creating on different platforms, not simply these designed by Apple.
  • Who does Apple’s Swift have an effect on? Apps constructed with Swift will be run on iOS gadgets courting again to iOS 7 or later, and OS X gadgets courting again to OS X 10.9 or later.
  • When is Apple’s Swift out there? Swift is available in the newest model of Xcode.
  • How will you get Apple’s Swift? Get the newest model of Swift by downloading Xcode from the Mac App Retailer or the Apple Developer Middle. As soon as Xcode is put in, Swift and the Goal-C compiler (LLVM) will likely be put in in your Mac.

SEE: 31 Mac keyboard shortcuts enterprise customers must know (free PDF) (TechRepublic)

How does Swift differ from Goal-C?

Whereas Apple hasn’t introduced plans to sundown the Goal-C language (the truth is, Apple remains to be updating it), Swift is quickly overtaking Goal-C to turn into extra standard on Apple’s platforms.

Goal-C possible nonetheless has a protracted life, as Apple has but to replace its personal Frameworks to be written in Swift. Till Swift 3.0, Apple won’t be together with the Swift runtime on iOS or OS X, leaving Xcode to package deal collectively the runtime into the iOS or OS X app to make sure binary compatibility.

Swift does deliver lots of trendy programming niceties to Apple’s platforms. This is a have a look at the primary variations between Goal-C and Swift.

Header information

Goal-C was primarily based on C, however added OOP paradigms to the language by object messaging. Due to that, Goal-C made use of header information that publicly declared its features and definitions.

Swift eliminates this apply, permitting builders to write down a single .swift file that accommodates typical header info, properties and the entire class defines right into a single file. Say goodbye to header information, and whats up to cleaner and leaner code.

SEE: All of TechRepublic’s cheat sheets and sensible individual’s guides


Goal-C and Swift are compiled languages, regardless of Swift having a REPL (Learn-Eval-Print Loop) for testing that sometimes solely helps interpreted languages.

The REPL is accessible within the command line and Xcode. Within Xcode, it is named Playgrounds, permitting builders to write down Swift code, and have it evaluated instantly, printing out the ends in the sidebar (Determine A). To create a brand new Swift Playground in Xcode, open Xcode and choose File | New | Playground. A brand new window will seem, and you’ll enter Swift code to check issues.

Determine A


Playgrounds are a spot to judge and check code with out creating a whole iOS or OS X undertaking first.

Picture: Cory Bohon/TechRepublic

Kind inference

With Goal-C and Swift, object varieties are strongly typed—which means, the compiler should know precisely what kind of object (string, array, dictionary, customized object, and many others.) must be saved in reminiscence for a selected variable. With Swift, Apple determined to maintain sturdy varieties, however enable the compiler to robotically infer the kind primarily based on the objects assigned to a variable.

This implies you may write code like the next snippet, and Swift will see that myVariable is a String kind, as a result of it has a String assigned to it.

let myVariable = "some string right here"

Builders can nonetheless carry out sturdy typing for readability by doing this, however it’s pointless. Nonetheless, it does add readability, particularly to builders which may be touching the codebase after you have labored on it.

let myVariable: String = "some string right here"

Accessible platforms

When Apple introduced Swift at WWDC 2014, the corporate reported that convention attendees have been utilizing one of many first publicly launched Swift apps: the WWDC app. It was developed partially in Swift, and allowed attendees to view session schedules, maps and extra.

Formally, iOS 7 and better help Swift; OS X 10.9 (Mavericks) and better help it as effectively. All variations of watchOS and tvOS have help for operating Swift-built apps.

How can I study and use Swift?

You may want a Mac, and if you may be creating for iOS, watchOS or tvOS, you may want a type of gadgets as effectively.

After you obtain and set up Xcode, the Goal-C and Swift compiler (LLVM) is put in in your Mac. At this level, opening Xcode will current choices for starting initiatives in both Swift or Goal-C.

The primary place to start out is with Playgrounds and the Swift REPL, the place you may study by taking part in with Swift’s options in an surroundings that will not mess up any in-flight apps, and with out the necessity to create any full testing iOS or OS X undertaking.

SEE: Methods to create Apple apps and widgets: Go from novice to professional with this coaching (TechRepublic Academy)

Remember to reap the benefits of Apple’s nice Swift sources, which embody these books about Swift which can be out there within the Apple Books app: 

What does Swift imply for enterprises and builders?

Swift is an open supply language that’s being adopted at a really speedy tempo. It permits builders to prototype and write iOS, OS X and different Apple platform apps sooner and with fewer bugs and crashes than ever earlier than.

Should-read developer content material

That is vital for enterprises, particularly companies which have made investments in Apple’s platforms, and investments in creating their very own B2B/enterprise apps, as a result of holding these apps updated has by no means been simpler.

As well as, Swift being open sourced signifies that the language will likely be expanded to different platforms, past simply what Apple has created. We’re already seeing Swift being ported to Linux and different platforms.

One potential space the place Swift will flourish is internet apps. Swift being ported to Linux signifies that Swift apps can now run on low-cost, low-maintenance Linux servers which can be already the cornerstone of current internet APIs and providers. There are already frameworks for Swift that make it so Linux-based server apps will be constructed inside Xcode, permitting companies to make the most of current Swift builders to construct the APIs and providers that iOS and OS X apps typically devour.

Extra sources

What’s new in Swift 2.0?

Apple launched Swift 2.0 at WWDC ’15, and it added many options and refinements. These are among the new options in Swift 2.0.

  • Swift is open supply with a brand new Linux port out there.
  • A brand new error dealing with mannequin utilizing attempt, throw, and catch key phrases.
  • It targets older variations of iOS and OS X. It is also safer, with the #out there block that permits you to wrap traces of code that will likely be executed on programs the place the framework is accessible.
  • SDKs at the moment are Swift-ier, due to Apple including generics and nullability to current Goal-C frameworks to make them interface higher with Swift code.

What’s new in Swift 3.0?

Apple launched Swift 3.0 at WWDC ’16; it was the primary main launch of Swift since Apple open sourced the language in December 2015. The brand new options in Swift 3.0 embody:

  • Refinements to the core language and normal library to rid the language of NS prefixes and different Goal-C holdovers.
  • Main additions to the Linux port of Swift.
  • The addition of the Swift Bundle Supervisor to make it simpler to handle dependencies.

What’s new in Swift 4.0?

Like with different Swift releases, 4.0 was introduced at WWDC ’17 and launched in beta type to builders alongside Xcode 9. This launch of Swift added fairly a couple of refinements and options to the programming language, together with:

  • New Codeable protocol that enables for straightforward serialization of information wrapped in structs.
  • String literals can now break into a number of traces utilizing the brand new “”” declaration (three units of quote marks) to open and shut the multiline string.
  • Strings obtained a serious overhaul, making them collections of characters.

What’s new in Swift 5.0?

Swift 5.0 ushered in additional enhancements for the most well-liked language for iOS and Mac growth by including many normal library additions like efficiency enhancements and extra.

The most important characteristic of Swift 5.0 was the declaration of ABI Stability and Binary Compatibility; each of those imply that the Swift normal libraries are integrated within the releases of macOS, iOS, tvOS and watchOS going ahead. These libraries now not have to be included in every app’s binary, and the app package deal will be a lot smaller.

What’s new in Swift 5.3?

Swift 5.3 was launched with Xcode 12 on September 16, 2020. This launch of Swift primarily targeted on refinements to the language itself and increasing the Swift ecosystem. 

The Swift group at Apple took the chance to optimize runtime efficiency by decreasing the codesize for Swift apps (particularly for SwiftUI apps), enhancing the reminiscence optimizations and decreasing the heap reminiscence utilization. 

On the developer facet of issues, Apple targeted on making errors extra exact and extra actionable with ideas within the compiler strategies, code completion was improved greater than 5x, and there is now higher runtime error messages, making it simpler to determine points once you encounter them throughout debugging.

Apple additionally expanded its platform help. Swift is now supported on Ubuntu, CentOS 8, Amazon Linux Z, Home windows (with Swift 5.3 solely), and AWS Lambda runtime surroundings.

As well as, Apple took into consideration many Swift Evolution strategies from the group. 

What’s new in Swift 5.4?

Swift 5.4 was launched on April 26, 2021 to all customers of Xcode 12.5. On the enhancements listing there have been many niceties, together with compiler enhancements, improved code completion when typing expressions and large enhancements for incremental compiles. 

On the coding facet, there are numerous additions from the Swift Evolution group, together with: 

  • Improved Implicit Member Syntax (SE-0287).

  • A number of variadic parameters in perform calls (SE-0284).

  • Outcome builders (SE-0289).

  • Native features help overloading (SE-10069).

As well as, Swift 5.4 introduces the flexibility to call a variable the identical as a perform, and property wrappers at the moment are supported for native variables. 

Swift Bundle Supervisor enhancements will also be present in Swift 5.4 and Xcode 12.5, together with the flexibility to declare packages executable targets (SE-0294).

What’s new in Swift 5.5?

Swift 5.5 was launched in beta type with Xcode 13 on June 7, 2021 at WWDC 2021. The principle enhancements with this launch focus on concurrency with the introduction of the async/await mechanism of performing duties that should carry out work and look ahead to one thing to finish earlier than persevering with. Study extra about concurrency in Swift 5.5 by watching the WWDC 2021 session entitled “Discover structured concurrency in Swift” on the Apple Developer web site, or by studying the Swift Concurrency documentation.

What’s Swift Playgrounds for iPad?

At WWDC ’16, Apple introduced the addition of Swift Playgrounds, an app that lets builders and starting coders program utilizing the Swift language on the iPad in a Playground surroundings that was pioneered on the Mac with Xcode 6.

At WWDC ’17, Apple introduced two new variations of Swift Playgrounds. Swift Playgrounds 1.5 is accessible instantly and offers the flexibility to interface with Bluetooth-connected gadgets like drones, Sphero and LEGO toys to deliver real-world programming for college kids and builders.

Additionally introduced at WWDC ’17 was Swift Playgrounds 2.0. This new model was made out there as a beta to builders on the convention and options built-in API documentation instruments, Swift 4.0 and Swift 3.2 help, help for the iOS 11 SDK, and help for utilizing Digicam and Augmented Actuality APIs.

Swift Playgrounds 3.0 was launched in Might 2019, and was a big replace to the Swift Playgrounds app that has obtained stability updates and enhancements—model 3.3.1 is now out there. Model 3.0 is important as a result of it added the flexibility to import your individual Swift information right into a playground, and share Swift information amongst your playgrounds. It additionally contains coding error strategies, darkish mode help, extra instruments for educators to construct out their very own Swift playground books and Swift model updates so the newest Swift code will be constructed inside the Swift Playgrounds app. 


The brand new Swift Playgrounds app displaying a full Swift / SwiftUI utility being constructed and developed on the iPad.

Picture: Apple, Inc.

With the introduction of Swift Playgrounds 4 at WWDC ’21, Apple added the flexibility to create iOS apps throughout the Swift Playgrounds utility on iPadOS 15. Doing this requires apps to be constructed with SwiftUI for the person interfaces and Swift for the programming language (you can’t use Goal-C or Interface Builder information within the construct course of). Apps constructed with the Swift Playgrounds app will be examined proper on the iPadOS gadget being constructed with, and may even be shipped to the App Retailer. This new model of Swift Playgrounds for iPadOS will likely be out there to iPad homeowners starting this fall within the App Retailer. 

Swift Playgrounds is a free app that may be downloaded for iPad from the App Retailer.

Extra sources

What’s SwiftUI?

At WWDC in June 2019, Apple launched SwiftUI, which is a brand new approach to create UIs for Swift apps. This set of instruments and APIs enable builders to write down declarative Swift syntax to outline and current a person interface, getting many new options that include
iOS 13

free of charge, together with:

  • Dynamic Kind.
  • Darkish Mode.
  • Localizations for frequent gadgets.
  • iOS accessibility options.

SwiftUI permits you to state what the interface ought to do, and iOS takes management in presenting that interface to your customers. You may create an inventory of things, after which describe the alignment, font and coloration for every merchandise all in code with out having to make the most of Interface Builder.

Utilizing the brand new Design Instruments in Xcode, you may see what the code is presenting to the person. The stay preview window will robotically sync with the code within the side-by-side editor to preview as you kind.

SwiftUI is native on all Apple platforms starting with iOS 13 and newer, together with iPhone, Mac, iPad, Apple Watch and Apple TV. Better of all, a UI that you just create for one gadget will robotically be translated (or will be translated with little work) to all platforms.

SwiftUI can be the best way you may simply port your iOS apps to Mac by including the Mac as a deployment choice in your iOS undertaking settings. This new framework will in the end result in mere accessible, extra maintainable, extra transportable apps for Apple’s platforms.

For extra info on implementing SwiftUI in your functions, take a look at the next WWDC 2019 session movies:

At WWDC 2020, Apple unveiled a brand new model of SwiftUI that added much more options for constructing total iOS, macOS, tvOS, and watchOS apps utilizing SwiftUI. Additionally they took a leap ahead for SwiftUI, making it the default approach to construct widgets for iOS 14. New options like outlines, grids and toolbars make SwiftUI much more highly effective and succesful than earlier than. 

WWDC ’21 caused a couple of new SwiftUI adjustments, together with increasing compatibility with macOS to make extra Mac builders change to the brand new UI structure system that SwiftUI brings about. Lots of the adjustments depend on bringing extra normal parts from the Mac interface over to SwiftUI, together with the multi-column view, and search views for macOS and iOS and a brand new low-level graphics structure view appropriate with SwiftUI to exchange the getting older drawRect from Swift and Goal-C.

Swift 5.5 and SwiftUI result in different niceties into the language. One such new characteristic known as AsyncImage, which is a brand new view for remotely loading pictures. Different niceties embody the flexibility so as to add swipe actions for listing rows, pull to refresh and tidying up the SwiftUI API for generally used gadgets.

Past the session movies above, that are nonetheless related, Apple additionally launched new session movies at WWDC 2021 that explains the entire new SwiftUI options: 

What’s Swift Bundle Supervisor?

Lately, the Swift Bundle Supervisor has picked up recognition amongst iOS and macOS builders as different open supply package deal managers have waned locally. The Swift Bundle Supervisor, typically abbreviated SPM, provides the flexibility beginning in Swift 3.0 and Xcode 8 to bundle collectively a dependent Swift undertaking or supply information right into a module that may simply be added and versioned by Git, then downloaded, constructed and embedded into an iOS, macOS, watchOS or tvOS undertaking by Xcode.

This package deal supervisor is constructed into Xcode and provides a straightforward approach to separate out reusable code that may be shared between a number of initiatives or a number of homeowners—within the case of open supply or cross-company sharing of initiatives. 

Constructing a module with SPM is simple and will be performed with a couple of traces of code and git repository. Find out about creating and utilizing a Swift Bundle in Xcode right here, or study extra about how the system works on the weblog.

What’s Swift’s model historical past?

  • Mid 2010: Improvement begins.
  • July 17, 2010: First Swift decide to the Swift GitHub repository.
  • June 2, 2014: Apple publicizes Swift at WWDC 2014, giving builders a pre-release model of Swift and Xcode 6.
  • September 15, 2014: Apple releases Swift 1.0 with the Gold Grasp of Xcode 6.
  • October 15, 2014: Swift 1.1 is launched with Xcode 6.1.
  • April 8, 2015: Swift 1.2 is launched with Xcode 6.3.
  • June 8, 2015: Apple publicizes Swift 2.0 at WWDC 2015, giving builders a pre-release model of Swift 2 and Xcode 7.
  • September 15, 2015: Apple releases Swift 2.0 with the Xcode 7 Gold Grasp construct.
  • October 20, 2015: Apple releases Swift 2.1 with the discharge of Xcode 7.1.
  • December 3, 2015: Apple publicizes the Swift 3.0 roadmap on GitHub.
  • March 21, 2016: Apple releases Swift 2.2 with the discharge of Xcode 7.3.
  • September 13, 2016: Apple releases Swift 3.0 with the discharge of Xcode 8.
  • March 27, 2017: Apple releases Swift 3.1.
  • June 5, 2017: Apple publicizes Swift 4.0 at WWDC ’17.
  • March 29, 2018: Apple releases Swift 4.
  • September 17, 2018: Apple releases Swift 4.2.
  • March 25, 2019: Apple releases Swift 5.0.
  • September 20, 2019: Apple releases Swift 5.1 with Xcode 11.
  • March 24, 2020: Apple releases Swift 5.2.
  • June 2020: Apple publicizes Swift 5.3 at WWDC ’20.
  • September 16, 2020: Apple releases Swift 5.3 with Xcode 12.
  • November 13, 2020: Apple releases Swift 5.3.1 with Xcode 12.1.

  • December 15, 2020: Apple releases Swift 5.3.2 with Xcode 12.2.

  • January 25, 2021: Apple releases Swift 5.3.3 with Xcode 12.3.

  • April 26, 2021: Apple releases Swift 5.4 with Xcode 12.5.

  • Might 25, 2021: Swift 5.4.1 launched. 
  • November 13, 2020: Apple releases Swift 5.3.1 with Xcode 12.1.
  • December 15, 2020: Apple releases Swift 5.3.2 with Xcode 12.2.
  • January 25, 2021: Apple releases Swift 5.3.3 with Xcode 12.3.
  • April 26, 2021: Apple releases Swift 5.4 with Xcode 12.5.
  • Might 25, 2021: Swift 5.4.1 launched. 
  • June 7, 2021: Apple reveals Swift 5.5 and SwiftUI 3, launched with Xcode 13 beta.
  • June 28, 2021: Apple releases Swift 5.4.2.

  • September 9, 2021: Swift 5.4.3 is launched.

  • September 20, 2021: Apple releases Xcode 13 with the Swift 5.5 programming language, together with the a lot awaited (no pun meant) async/await performance, and new SwiftUI options introduced at WWDC ’21.

Extra sources

Editor’s be aware: This text has been up to date to mirror the newest launch of Swift.

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