how to decode array of custom objects decodable
Generated on 8/22/2024
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To decode an array of custom objects that conform to the Decodable protocol in Swift, you can use the JSONDecoder class. Here's a basic example of how you might do this:
import Foundation
// Define your custom object
struct CustomObject: Decodable {
let id: Int
let name: String
}
// JSON data representing an array of CustomObject
let jsonData = """
[
{"id": 1, "name": "Object One"},
{"id": 2, "name": "Object Two"}
]
""".data(using: .utf8)!
// Decode the JSON data
do {
let decoder = JSONDecoder()
let objects = try decoder.decode([CustomObject].self, from: jsonData)
print(objects)
} catch {
print("Failed to decode JSON: \(error)")
}
In this example, CustomObject is a struct that conforms to Decodable. The JSONDecoder is used to decode a JSON array into an array of CustomObject instances. Make sure your JSON data matches the structure of your custom object.
For more advanced topics related to Swift, such as handling concurrency or performance optimizations, you might find sessions like "Migrate your app to Swift 6" and "Explore Swift performance" from WWDC 2024 helpful. These sessions cover topics like data-race safety and memory layout, which can be crucial when working with complex data structures in Swift.
Explore Swift performance
Discover how Swift balances abstraction and performance. Learn what elements of performance to consider and how the Swift optimizer affects them. Explore the different features of Swift and how they’re implemented to further understand the tradeoffs available that can impact performance.
A Swift Tour: Explore Swift’s features and design
Learn the essential features and design philosophy of the Swift programming language. We’ll explore how to model data, handle errors, use protocols, write concurrent code, and more while building up a Swift package that has a library, an HTTP server, and a command line client. Whether you’re just beginning your Swift journey or have been with us from the start, this talk will help you get the most out of the language.
Migrate your app to Swift 6
Experience Swift 6 migration in action as we update an existing sample app. Learn how to migrate incrementally, module by module, and how the compiler helps you identify code that’s at risk of data races. Discover different techniques for ensuring clear isolation boundaries and eliminating concurrent access to shared mutable state.
What’s new in SwiftData
SwiftData makes it easy to add persistence to your app with its expressive, declarative API. Learn about refinements to SwiftData, including compound uniqueness constraints, faster queries with #Index, queries in Xcode previews, and rich predicate expressions. Join us to explore how you can use all of these features to express richer models and improve performance in your app. To discover how to build a custom data store or use the history API in SwiftData, watch “Create a custom data store with SwiftData” and “Track model changes with SwiftData history”.