Swift share array between threads5/26/2023 ![]() ![]() Concurrent Queue Parallelism Concurrency Basics of Multithreading Main Thread (UI Thread) vs. ![]() In this article, we will learn the following: TABLE OF CONTENTS What Is Multithreading Serial Queue vs. Second, use a type alias to keep your code readable and easier to understand.Photo by John Anvik on Unsplash Introduction First, use dictionaries when it is appropriate to use them. The key takeaways for this episode are simple but powerful. The compiler immediately notifies us that we made a typo. We can't make this mistake if we replace the array of dictionaries with an array of User objects. The result is nil, because we misspelled the key ( firstt instead of first). We ask the array of users for the first element and access the value for key firstt. The next example illustrates the danger of dictionaries and stringly typed code. Some forms of stringly typing are obvious while others are more subtle. When strings, and very often string literals, are used instead of a more appropriate type, we speak of stringly typed code. Bugs and Stringly Typed Codeĭictionaries are useful, but it is important to know when (not) to use them. The array literal we assign to users is easier on the eyes and, more importantly, the compiler makes sure we don't make typos. The declaration of users is easier to read and we don't need a type alias. It is true that we added a few additional lines of code to implement the User struct, but the benefits far outweigh those handful of lines of code. ![]() Take a look at the updated example below. It is easier and more convenient to create a struct that encapsulates the data the dictionary stores. I rarely use arrays of dictionaries in Swift. Notice how the declaration of users becomes much easier to read and understand. import FoundationĪs the name suggests, a type alias is nothing more than a named alias for a type. We can simplify this by defining a type alias for the elements of the array. ![]() The elements the array holds are of type. We assign an empty array, an array of dictionaries, to users. The syntax may look confusing, but it is pretty straightforward. As I mentioned earlier, we can't rely on type inference if the array is empty. We don't need to specify the type of the array thanks to type inference. In this example, we create an array of dictionaries using an array literal. The array literal is a bit more complex, but that is the only difference. import FoundationĪn array of dictionaries is no different. We explicitly specify the type of the array to make it clear the array is of type, an array of integers. We can't take advantage of type inference if we want to create an empty array of integers. The compiler can infer the type of the array by inspecting the elements of the array literal. An array literal is the most straightforward option. There are several ways to create an array in Swift. Storing Elements in an Arrayįire up Xcode and create a playground by choosing the Blank template from the iOS > Playground section. In this episode, I show you how to store dictionaries in an array and I show you why an array of dictionaries is usually not what you need or even want. The type of data an array stores can sometimes be quite complex, though. An array in Swift can contain any type of data, values types as well as reference types. ![]()
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