如何在swift中创建固定大小的二维数组

var twoDArray: [[Int]] = [
    [1, 2, 3],
    [4, 5, 6],
    [7, 8, 9]
]

let rows = 3
let columns = 3
var twoDArray = Array(repeating: Array(repeating: 0, count: columns), count: rows)

struct TwoDArray<T> {
    private var array: [[T]]
    
    init(rows: Int, columns: Int, defaultValue: T) {
        array = Array(repeating: Array(repeating: defaultValue, count: columns), count: rows)
    }
    
    subscript(row: Int, column: Int) -> T {
        get { return array[row][column] }
        set { array[row][column] = newValue }
    }
}

var myArray = TwoDArray<Int>(rows: 3, columns: 3, defaultValue: 0)
myArray[1, 1] = 5 // 设置第二行第二列的值为5