Hello everyone. I was a building a test app when I encountered this error: I'm new to indices and am a bit confused by them. Can someone please explain the error to me and show me a possible solution to it? Many thanks! Here is my code: import SwiftUI struct GameView: View { @StateObject var viewModel = GameViewModel() var body: some View { ZStack { GameColor.main.ignoresSafeArea() VStack { Text(viewModel.progressText) .padding() Spacer() Text(viewModel.questionText) .font(.title) .multilineTextAlignment(.center) .padding() Spacer() Spacer() HStack { ForEach(0..<viewModel.answerIndices.count, id: \.self) { index in AnswerButton(text: viewModel.answerIndices[index]) { // ForEach(viewModel.answerIndices) { index in // AnswerButton(text: viewModel.answerText(for: index)) { viewModel.makeSelectionForCurrentQuestion(at: index) } .background(viewModel.colorForButton(at: index)) .disabled(viewModel.selectionWasMade) } } if viewModel.selectionWasMade { Button(action: viewModel.advanceGameState, label: { BottomText(str: "Next") }) } }.padding(.bottom) } .navigationBarHidden(true) .background(resultsNavigationLink) } private var resultsNavigationLink: some View { NavigationLink( destination: ResultsView(viewModel: ResultsViewModel(selectionCount: viewModel.selectionCount, gameStartTime: viewModel.gameStartTime, gameEndTime: Date())), isActive: .constant(viewModel.gameIsOver), label: { EmptyView() }) } } struct AnswerButton: View { let text: String let onClick: () -> Void var body: some View { Button(action: { onClick() }) { Text(text) } .padding() .border(Color.blue, width: 4) } } struct ContentView_Previews: PreviewProvider { static var previews: some View { NavigationView { GameView() } } } (Above is the view; this is the model: import SwiftUI class GameViewModel: ObservableObject { @Published var game = Game() var questionText: String { game.currentQuestion.questionText } var answerIndices: Range<Int> { game.currentQuestion.possibleAnswers.indices } var correctAnswerIndex: Int { game.currentQuestion.correctAnswerIndex } var progressText: String { "Question \(game.currentQuestionIndex + 1) / \(game.questionCount)" } var selectionWasMade: Bool { game.selections[game.currentQuestion] != nil } var selectionCount: (Int, Int) { game.selectionCount } var gameIsOver: Bool { game.gameIsOver } var gameStartTime: Date { game.startTime } func answerText(for index: Int) -> String { game.currentQuestion.possibleAnswers[index] } func advanceGameState() { game.advanceGameState() } func makeSelectionForCurrentQuestion(at index: Int) { game.makeSelection(at: index) } func colorForButton(at buttonIndex: Int) -> Color { guard let selectedIndex = game.selections[game.currentQuestion], selectedIndex == buttonIndex else { return .clear } if selectedIndex == correctAnswerIndex { return .green } else { return .red } } } Thanks for the help in advance!