ios - Swift: Two-dimensional array error index out of range

Question

I'm trying to add new item into two-dimensional array but I'm getting this error Index out of range

Here is my implementation:

var array = [[Int]]()
array[0][0] = 1  // <-- Index out of range error

Any of you knows why I'm getting this error or if there is work around ?

I really appreciate you help

Answer 1

You have declared an Array of Arrays of Ints.

To append something to that array, you have to create a new Array of Int to append to it.

After you have appended one or more Arrays of Int, you can then modify those values, or append additional Int values to the 2nd-level array:

    var array = [[Int]]()

    print(array)
    // output is: []

    // append an array of One Int
    array.append([1])

    print(array)
    // output is: [[1]]
    
    // append an array of Three Ints
    array.append([1, 2, 3])

    // append an array of Six Ints
    array.append([4, 5, 6, 7, 8, 9])

    print(array)
    // output is: [[1], [1, 2, 3], [4, 5, 6, 7, 8, 9]]

    // modify the value of the 2nd Int in the 2nd array
    array[1][1] = 100
    
    print(array)
    // output is: [[1], [1, 100, 3], [4, 5, 6, 7, 8, 9]]
    
    // append a new Int to the 2nd array
    array[1].append(777)
    
    print(array)
    // output is: [[1], [1, 100, 3, 777], [4, 5, 6, 7, 8, 9]]