iosswiftdictionaryswift2

Ordered map in Swift

Is there any built-in way to create an ordered map in Swift 2? Arrays [T] are sorted by the order that objects are appended to it, but dictionaries [K : V] aren't ordered.

For example

var myArray: [String] = []
myArray.append("val1")
myArray.append("val2")
myArray.append("val3")

//will always print "val1, val2, val3"
print(myArray)


var myDictionary: [String : String] = [:]
myDictionary["key1"] = "val1"
myDictionary["key2"] = "val2"
myDictionary["key3"] = "val3"

//Will print "[key1: val1, key3: val3, key2: val2]"
//instead of "[key1: val1, key2: val2, key3: val3]"
print(myDictionary)

Are there any built-in ways to create an ordered key : value map that is ordered in the same way that an array is, or will I have to create my own class?

I would like to avoid creating my own class if at all possible, because whatever is included by Swift would most likely be more efficient.

Solution

  • You can order them by having keys with type Int.

    var myDictionary: [Int: [String: String]]?

    or

    var myDictionary: [Int: (String, String)]?

    I recommend the first one since it is a more common format (JSON for example).