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Questions tagged [swift]

Swift is a general-purpose programming language developed by Apple Inc first released in 2014 for its platforms and Linux. Swift is open-source. Use the tag only for questions about language features or requiring code in Swift. Use the tags [ios], [ipados], [macos], [watch-os], [tvos], [swiftui], [cocoa-touch], and [cocoa] for (language-agnostic) questions about the platforms or frameworks.

Swift is an application and systems programming language introduced by Apple on June 2, 2014, and distributed as open source. Swift interoperates with Objective-C and Cocoa/Cocoa Touch APIs for Apple's iOS, macOS, watchOS, tvOS, and iPadOS operating systems.

Current stable version is Swift 5.8.0 released on November 1, 2022 (download).

  • Swift is open-source, available on GitHub
  • Swift >=2.2 includes support for Swift on a Linux platform.
  • Swift >=5.3 includes support for Swift on a Windows platform.

Please use the tag for questions relating to OpenStack's object/blob store, and the tag for questions relating to the parallel scripting language.

Swift promises to modernize the developer experience over what Objective-C provides, offering features like:

  • Generics
  • Type safety
  • Type inference
  • Namespaces
  • Improved safety (some protection from overflow, use-before-initialization, etc.)
  • Higher-order functions (map, filter, sort)

among others.

The Swift syntax retains some elements from Objective-C while providing an extensive new vocabulary for its new features.

The language can use existing iOS and macOS frameworks, like Cocoa and Cocoa Touch, and can sit side-by-side with Objective-C in applications. Swift applications compile into standard binaries and can be run on OS X 10.9, iOS 7 (or higher), tvOS and watchOS.

Timeline

  • Swift 2.0 was introduced by Apple at WWDC on 8th June 2015. They added new features like the "Error handling model" with try, throw and catch.

  • Swift 2.2 was introduced with Xcode 7.3 on 21st March 2016. (release notes)

  • Swift 3.0 was introduced by Apple at WWDC on 13th June 2016, with the news that Swift will come to non-Apple platforms (Windows, Linux, Android, Raspberry Pi, and so on). (release notes)

  • Swift 3.1 was introduced with Xcode 8.3 on 27th March 2017. (release notes)

  • Swift 4.0 was introduced by Apple at WWDC on 5th June 2017. (release notes)

  • Swift 4.1 was introduced with Xcode 9.3 on 29th March 2018. (release notes)

  • Swift 4.2 was introduced by Apple at WWDC on 4th June 2018. (release notes)

  • Swift 5.0 was introduced with Xcode 10.2 on 25th March 2019. (release notes)

  • Swift 5.1 was introduced with Xcode 11 on 20th September 2019. (release notes)

  • Swift 5.2 was introduced with Xcode 11.4 on 24th March 2020. (release notes)

  • Swift 5.3 was introduced with Xcode 12 on 16th September 2020. (release notes)

  • Swift 5.4 was introduced with Xcode 12.5 on 26th April 2021. (release notes)

  • Swift 5.5 was introduced with Xcode 13 on 20th September 2021. (release notes)

  • Swift 5.6 was introduced with Xcode 13.3 on 14th March 2022. (release notes)

  • Swift 5.7 was introduced with Xcode 14 on 12th September 2022. (release notes)

  • Swift 5.8 was introduced with Xcode 14.3 on 30th March 2023. (release notes)

Resources

References

Books

Other resources

Related Tags

329921 questions
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Global constants file in Swift

In my Objective-C projects I often use a global constants file to store things like notification names and keys for NSUserDefaults. It looks something like this: @interface GlobalConstants : NSObject extern NSString…
user1028028
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Read and write a String from text file

I need to read and write data to/from a text file, but I haven't been able to figure out how. I found this sample code in the Swift's iBook, but I still don't know how to write or read data. import Cocoa class DataImporter { /* DataImporter…
Jorge Vega Sánchez
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How do I add 1 day to an NSDate?

Basically, as the title says. I'm wondering how I could add 1 day to an NSDate. So if it were: 21st February 2011 It would become: 22nd February 2011 Or if it were: 31st December 2011 It would become: 1st January 2012.
Andrew
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How do I check when a UITextField changes?

I am trying to check when a text field changes, equivalent too the function used for textView - textViewDidChange so far I have done this: func textFieldDidBeginEditing(textField: UITextField) { if self.status.text == "" &&…
user4184036
365
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32 answers

What is the difference between `let` and `var` in Swift?

What is the difference between let and var in Apple's Swift language? In my understanding, it is a compiled language but it does not check the type at compile time. It makes me confused. How does the compiler know about the type error? If the…
Edward
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How do I print the type or class of a variable in Swift?

Is there a way to print the runtime type of a variable in swift? For example: var now = NSDate() var soon = now.dateByAddingTimeInterval(5.0) println("\(now.dynamicType)") // Prints "(Metatype)" println("\(now.dynamicType.description()") //…
Matt Bridges
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How can I use String substring in Swift 4? 'substring(to:)' is deprecated: Please use String slicing subscript with a 'partial range from' operator

I have the following simple code written in Swift 3: let str = "Hello, playground" let index = str.index(of: ",")! let newStr = str.substring(to: index) From Xcode 9 beta 5, I get the following warning: 'substring(to:)' is deprecated: Please use…
Adrian
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356
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Removing duplicate elements from an array in Swift

I might have an array that looks like the following: [1, 4, 2, 2, 6, 24, 15, 2, 60, 15, 6] Or, really, any sequence of like-typed portions of data. What I want to do is ensure that there is only one of each identical element. For example, the above…
Altair357
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After upgrading to Xcode 11.2 from Xcode 11.1, app crashes due to _UITextLayoutView

After upgrading to Xcode 11.2 from Xcode 11.1 my app crashes: *** Terminating app due to uncaught exception 'NSInvalidUnarchiveOperationException', reason: 'Could not instantiate class named _UITextLayoutView because no class named…
Sudhakar Tharigoppula
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22 answers

Safe (bounds-checked) array lookup in Swift, through optional bindings?

If I have an array in Swift, and try to access an index that is out of bounds, there is an unsurprising runtime error: var str = ["Apple", "Banana", "Coconut"] str[0] // "Apple" str[3] // EXC_BAD_INSTRUCTION However, I would have thought with all…
Craig Otis
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Instantiate and Present a viewController in Swift

Issue I started taking a look on the Swift Programming Language, and somehow I am not able to correctly type the initialization of a UIViewController from a specific UIStoryboard. In Objective-C I simply write: UIStoryboard *storyboard =…
E-Riddie
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How to detect if app is being built for device or simulator in Swift

In Objective-C we can know if an app is being built for device or simulator using macros: #if TARGET_IPHONE_SIMULATOR // Simulator #else // Device #endif These are compile time macros and not available at runtime. How can I achieve the same…
Rafał Sroka
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Convert an NSURL to an NSString

I have an app where the user can choose an image either from the built-in app images or from the iphone photo library. I use an object Occasion that has an NSString property to save the imagePath. Now in the case of the built-in app images I do get…
Ali
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Determining if Swift dictionary contains key and obtaining any of its values

I am currently using the following (clumsy) pieces of code for determining if a (non-empty) Swift dictionary contains a given key and for obtaining one (any) value from the same dictionary. How can one put this more elegantly in Swift? // excerpt…
Drux
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42 answers

Move view with keyboard using Swift

I have an app that has a text field on the lower half of the view. This means that when I go to type in the text field the keyboard covers the textfield. How would I go about moving the view upwards while typing so I can see what i'm typing and then…
Alex Catchpole
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