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Just started using Swift and I'm getting pissed at a few elements. First is that most standard stuff are structs rather than objects, which means they're passed in as values rather than pointers as I'm used to. The other thing is that using the optional element system is really annoying.

If I am trying to declare an array without putting anything in it, I declare it like this:

var theArray : [Int]

In order to put anything in it, I would declare it like this:

var theArray : [Int]?

Then add objects as follows:

theArray[someIndex] = someInt
//or
theArray.append(someInt)

However, I get an error. In Java, I could have just initialized an array with a length, which would have given me an a fixed-size array with all 0's.

The problem, summarized in a sentence, is adding elements to Swift arrays that have been initialized without values. How do you do this?

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    you have declared the array, you haven't intialized it yet. @zellb 's answer seems like a good example of an actually initialized without values array. And by the way, including the error you're getting would be a good idea in general for your questions Commented Jan 26, 2015 at 19:04

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In order to initialize an empty array use:

var theArray : [Int] = []

then add elements by using append method. What you currently did is that you just declared it in the first case non optional and in the second case as an optional variable typed as int array without initializing it.

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If you want the array to contain Int types, of course there are many ways to declare that, based on implicit or explicit type inference. These are all valid declarations of an array containing Int types

var array1 = [Int]()
var array2: [Int] = []
var array3 = Array<Int>()
var array4: Array<Int> = []

If you want an array of a certain size, with the values initialized to a certain value you can use, in this example you'll get an Array<Int> with 5 elements, all initialised to 0

var array = Array(count: 5, repeatedValue: Int(0))
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Here you go:

var theArray = Array(count:[the length you want], repeatedValue:Int(0))

This will replicate the Java behaviour.

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