Storing and getting data form a Array of Arrays in Swift

Question

I'm working on Swift and I've some problems on multidimensional arrays. In playground, I test this code:

//some class
class Something {
    var name:String = ""
}

//i create an array (will store arrays)
var array = [NSArray]()

//create some Something objects
var oneSomething:Something = Something()
var twoSomething:Something = Something()

//fill Something names for sample
oneSomething.name = "N1"
twoSomething.name = "N2"

//create an array of Something's
var array2 = [Something]()

//append the two objets to array2
array2.append(oneSomething)
array2.append(twoSomething)

//append array2 to array N times just for testing
array.append(array2)
array.append(array2)

//on playground I test what I'm storing:
array[0]
array[0][0]
array[0][0].name

And this is the result I'm getting on the last 3 lines:

enter image description here

So, in the first line I access first level of arrays correctly, in the second line I access second line correctly two... but... in the third line I get 'nil' instead name of the Something object. What I'm doing wrong, how can I store and get multidimensional arrays in this example.

Thanks.

Bartłomiej Semańczyk · Accepted Answer · 2015-03-15 22:52:04Z

2

Because you declared:

var array = [NSArray]()

instead of:

var array = [[Something]]()

NSArray comes from Objective-C and it is not clear for Swift what is inside, so compiler doesn't know what type of objects that array contains.

However if you want to leave var array = [NSArray]() you must cast it:

(array[0][0] as Something).name

to tell the compiler that this is Something type. Then compiler knows about properties of that object. Otherwise this is AnyObject and its properties are unknown.

edited Mar 15, 2015 at 22:52

answered Mar 15, 2015 at 22:45

Bartłomiej Semańczyk

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Comments

jfgrang · Accepted Answer · 2015-03-15 22:52:31Z

2

The problem is that you are putting an object Something inside the array.

You need to unwrap it as the object type

if let object = array[0][0] as? Something {
    object.name
}

or you need to define the array as an array containing Something object

//i create an array (will store arrays)
var array = [Array<Something>]()
...
array[0][0].name

Regards

answered Mar 15, 2015 at 22:52

jfgrang

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