Swift provides a number of map methods to transform elements in Swift collections and return the transformed data in a new Array. The transform is supplied in a trailing closure to the map function. This article looks at Map, FlatMap and CompactMap on collections in Swift as well as MapValues in Dictionary.
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A dictionary stores a list of key/value pairs in an unordered structure that is fast and efficient at adding elements and finding elements by a key. Each element in the dictionary is identified using its key, which is a hashable type such as a string or number.
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TabularData was introduced in iOS 15 and can be used to load data from csv or json format into a DataFrame to explore and manipulate. This is not Python Pandas, but it does provide some basic functionality for exploring data and is fast and efficient. In this article, the data on the deaths from Covid is loaded, …
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Dependency Injection is a technique to pass in one or more dependent object to another object. This article will build on the Weather App to pass in the weather service to the weather ViewModel at initialisation. This will allow the use of a mock weather service to test the ViewModel in unit tests without requiring any …
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Code style can be a controversial topic and lead to some passionate debates between developers. The use of a tool to enforce a set of rules on style can be very helpful to avoid contentious arguments and ensure the code is consistent throughout a project. SwiftLint can easily be incorporated into Xcode projects to flag …
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Last week, we retrieved weather data from Open Weather API to demonstrate how to parse JSON data. The weather data is retrieved asynchronously, which may result in a delay before the UI is updated. This article shows how to display a progress view while the data is being fetched, to provide feedback that something is …
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Reading JSON data from local files and url is now much easier with codeable in Swift 5. This article shows how to load JSON data from a local file as well as from the open weather data api.
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Many shapes and patterns can be created using Path and Canvas in SwiftUI. It would be great to be able to save these as images in the Photo Library. This is possible using UIKit, by first converting the SwiftUI View to UIImage and then saving this image to Photos.
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I discovered a bug in the game I had written on Tic Tac Toe. When the board is in a certain state, the system did not take the obvious winning move. It still won the game, but with an extra move required. This article details how to write a failing unit test to reproduce the issue and how to update the minimax …
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A tab bar is presented at the bottom of the screen in iOS apps and is used for navigation between the major sections of an app. TabView is used in SwiftUI to easily add multiple tabs to the main view.
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