Caroline Caroline - 7 months ago 26
Swift Question

Multidimensional arrays in Swift

Edit: As Adam Washington points out, as from Beta 6, this code works as is, so the question is no longer relevant.

I am trying to create and iterate through a two dimensional array:

var array = Array(count:NumColumns, repeatedValue:Array(count:NumRows, repeatedValue:Double()))

array[0][0] = 1
array[1][0] = 2
array[2][0] = 3
array[0][1] = 4
array[1][1] = 5
array[2][1] = 6
array[0][2] = 7
array[1][2] = 8
array[2][2] = 9

for column in 0...2 {
for row in 0...2 {
println("column: \(column) row: \(row) value:\(array[column][row])")

}
}


However, this is the output I get:

column: 0 row: 0 value:3.0
column: 0 row: 1 value:6.0
column: 0 row: 2 value:9.0
column: 1 row: 0 value:3.0
column: 1 row: 1 value:6.0
column: 1 row: 2 value:9.0
column: 2 row: 0 value:3.0
column: 2 row: 1 value:6.0
column: 2 row: 2 value:9.0


It looks as if the last column in the row is overwriting the other column values.

Am I declaring it wrong?

Edit: Perhaps a picture from the Playground would help:

Captured from Playground

Rod Rod
Answer

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()))
}