How does the didLoad method differ from viewWillAppear in the lifecycle of UI components?

The viewDidLoad method is called once in the lifecycle of a UIViewController after its view has been loaded into memory. This is typically where initial interface setup, data initialization, and other components that do not depend on the visibility of the screen are performed.

The viewWillAppear method is called every time before the view controller's view appears on the screen. This is the place to update the UI, for example, updating data that may have changed or configuring elements that should be current each time.

Example:

override func viewDidLoad() {
    super.viewDidLoad()
    // UI setup, data initialization
}

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    // Update data that may change
}