Syntax to create Dictionary in Swift

问题

As far as I know there are two ways to create an empty dictionary in swift

var randomDict = [Int:Int]()

or

var randomDict = Dictionary<Int, Int>()

Is there any difference between these? Both versions seems to work just the same.

回答1:

No, both are same. From Apple's Book on Swift:

The type of a Swift dictionary is written in full as Dictionary<Key, Value> You can also write the type of a dictionary in shorthand form as [Key: Value]. Although the two forms are functionally identical, the shorthand form is preferred.

So

var randomDict = [Int:Int]()

and

var randomDict = Dictionary<Int, Int>()

both calls the initializer which creates an empty dictionary and are basically the same in different form.

回答2:

A third way you could do it is:

var randomDict:[Int:Int] = [:]

They're all equivalent as far as the code goes. I prefer one of the shorthand versions.

来源：https://stackoverflow.com/questions/29354511/syntax-to-create-dictionary-in-swift