Addressing a multi-dimensional array of objects in Swift - arrays

Question

Extreme newbie Swift syntax question...
Trying to address a multidimensional array of UIImageView objects and getting the error
Cannot subscript a value of type [[UIImageView]] with an index of
type UInt32.
I thought I was creating an NxN array of UIImageView objects but I guess not?
Thanks All!
func loadDefaultImages()
{
var pictures : [[UIImageView]] = [];
let MaxRows: UInt32 = 4
let MaxCols: UInt32 = 4
var row: UInt32
var col: UInt32
for (row = 0; row <= MaxRows; row++)
{
for (col = 0; col <= MaxCols; col++)
{
var newImage = UIImageView(image: UIImage(named: "first"))
pictures[row][col] = UIImageView() /* Error on this statement */
}
}
}

Answer 1

Initially, your pictures array will not contain any elements, (i.e. it will evaluate to []). As you try to set pictures[0][0], you're trying to reference both a row and column that do not exist yet.
Instead, you could build up the array as you go, like this:
func loadDefaultImages() {
var pictures : [[UIImageView]] = [];
let MaxRows: UInt32 = 4
let MaxCols: UInt32 = 4
for _ in 0..<MaxRows {
var aRow : [UIImageView] = []
for _ in 0..<MaxCols {
let newImage = UIImageView(image: UIImage(named: "first"))
aRow.append(newImage)
}
pictures.append(aRow)
}
}
However, a neater way to do this would be to create the array with a default size using the count, repeatedValue function, like so:
func loadDefaultImages() {
let MaxRows: Int = 4
let MaxCols: Int = 4
var pictures = [[UIImageView?]](count: MaxRows, repeatedValue: [UIImageView?](count: MaxCols, repeatedValue: nil))
for row in 0..<MaxRows {
for col in 0..<MaxCols {
let newImage = UIImageView(image: UIImage(named: "first"))
pictures[row][col] = newImage
}
}
}