Multidimensional arrays in Swift

For future readers, here is an elegant solution(5x5):

var matrix = [[Int]](repeating: [Int](repeating: 0, count: 5), count: 5)

and a dynamic approach:

var matrix = [[Int]]() // creates an empty matrix
var row = [Int]() // fill this row
matrix.append(row) // add this row

As stated by the other answers, you are adding the same array of rows to each column. To create a multidimensional array you must use a loop

var NumColumns = 27
var NumRows = 52
var array = Array<Array<Double>>()
for column in 0..NumColumns {
    array.append(Array(count:NumRows, repeatedValue:Double()))
}

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

for first in array {
    for second in first {
        println("value \(second)")
    }
}

To achieve what you're looking for you need to initialize the array to the correct template and then loop to add the row and column arrays:

var NumColumns = 27
var NumRows = 52
var array = Array<Array<Int>>()
var value = 1

for column in 0..NumColumns {
    var columnArray = Array<Int>()
    for row in 0..NumRows {
        columnArray.append(value++)
    }
    array.append(columnArray)
}

println("array \(array)")

Your problem may have been due to a deficiency in an earlier version of Swift or of the Xcode Beta. Working with Xcode Version 6.0 (6A279r) on August 21, 2014, your code works as expected with this output:

column: 0 row: 0 value:1.0
column: 0 row: 1 value:4.0
column: 0 row: 2 value:7.0
column: 1 row: 0 value:2.0
column: 1 row: 1 value:5.0
column: 1 row: 2 value:8.0
column: 2 row: 0 value:3.0
column: 2 row: 1 value:6.0
column: 2 row: 2 value:9.0

I just copied and pasted your code into a Swift playground and defined two constants:

let NumColumns = 3, NumRows = 3

Tags:

Arrays

Swift