arrays - Swift 追加到二维数组

Question

我试图在 Swift 中将一个值附加到二维数组，但它在第 8 行向我抛出“索引超出范围”错误

private var cards : [[Int]] = [[]]

init() {
    //Fill cards array by adding all cards
    for i in 0...12{
        for x in 0...3{
            cards[0].append(i+2)    //append card number... 2,3,4,5 etc
            cards[1].append(x)      //append card type... hearts, diamonds, clubs and spades
                                    //with a value which represents it (0, 1, 2 and 3)
        }
    }
}

Swift code

Answer 1

您不能使用 cards[0] 访问 cards 的内部数组，因为您将 cards 初始化为空数组，因此cards.count = 0，所以 cards[0] 不存在。

private var cards = [[Int]]()

init() {
    //Fill cards array by adding all cards
    for i in 0...12{
        for x in 0...3{
            cards.append([i+2,x])
        }
    }
}