Syntax explanation: square brackets in Swift

Question

I'm studying Swift and got confusing with following syntax:

var treasures: [Treasure] = []

Treasure is custom class, declared as follow:

class Treasure: NSObject { }

In Objective-C square brackets mean method, but what do they mean in Swift?

Answer 1

Ok, this is the meaning of

var treasures: [Treasure] = []

• var: you are declaring a variable
• treasures: the name of your variable
• [Treasure]: the type of your variable, in this case the type is Array of Treasure, the compiler will allow you to insert only object of type Treasure in your Array
• []: the actual object (Array) referenced by your variable, in this case an empty Array.

E.g. if you want the Array to hold 2 elements you can write

var treasures: [Treasure] = [Treasure(), Treasure()]

Hope this helps.

Update: My example can also be written this way

var treasures = [Treasure(), Treasure()]

Infact thanks to the Type Inference the compiler can deduce the type of the variable treasures looking at the type of the assigned value.