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Jack Hayton
Jack Hayton

Reputation: 363

Dictionaries not working inside a struct SWIFT

Why is this not working!? 

struct ChocolateBox {
    var caramelDelight = []
    caramelDelight["flavor"] = "caramel"
}

I tried this without the struct, still doesn't work:

var caramelDelight = []
caramelDelight["flavor"] = "caramel"

I have to add initial values into the array for it to work, for example:

var caramelDelight = ["test":"test"]
caramelDelight["flavor"] = "caramel"

Please explain.

Upvotes: 1

Views: 282

Answers (2)

Eric Aya
Eric Aya

Reputation: 70098

Your var caramelDelight = [] doesn't create an empty dictionary.

To create an empty dictionary use [:]() and specify the types of the keys and values, example: var caramelDelight = [String:String]().

There's also this alternative syntax: var caramelDelight: [String:String] = [:].

Also to modify the var in your struct you need to create an instance of the struct first:

struct ChocolateBox {
    var caramelDelight = [String:String]()
}

var cb = ChocolateBox()
cb.caramelDelight["flavor"] = "caramel"

println(cb.caramelDelight)  // [flavor: caramel]

UPDATE:

You can also create an initializer for your struct if you need to prepopulate the dictionary:

struct ChocolateBox {
    var caramelDelight: [String:String]
    init(dict: [String:String]) {
        self.caramelDelight = dict
    }
}

var cb = ChocolateBox(dict: ["flavor": "caramel"])

Of course then you can update the dictionary as usual:

cb.caramelDelight["color"] = "brown"

println(cb.caramelDelight)  // [color: brown, flavor: caramel]

Upvotes: 2

Epic Defeater
Epic Defeater

Reputation: 2147

That is because caramelDelight is actually an array, not a dictionary. You can fix that by doing var caramelDelight: [String:String] = [:]

Upvotes: 1

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