Dictionaries

Dictionaries

Dictionary<KeyType, ValueType>

var pitchers = [

    "Wang": 40,

    "Kuo": 56,

]

Add new item

pitchers["Chen"] = 16

//pitchers =["Kuo": 56, "Wang": 40, "Chen": 16]

println("There are \(pitchers.count) pitchers in the dictionary.")
//Console output: There are 3 pitchers in the dictionary.

Change item value

pitchers["Kuo"] = 00

//pitchers =["Kuo": 0, "Wang": 40, "Chen": 16]

for loop: Iterating Over the dictionary

for (surname, number) in pitchers {

    println("\(surname): \(number)")

}

//Console output: 

Kuo: 0

Wang: 40

Chen: 16

for surname in pitchers.keys {

    println("Pitcher Surname: \(surname)")

}

for number in pitchers.values {

    println("Pitcher Number: \(number)")

}

//Console output:

Pitcher Surname: Kuo

Pitcher Surname: Wang

Pitcher Surname: Chen

Pitcher Number: 0

Pitcher Number: 40

Pitcher Number: 16

================================

Declare an empty dictionary

var airlineCode = Dictionary<String, String>()

println("There are \(airlineCode.count) data.")

var airlineCode = [String: String]()

//Console output: There are 0 data.
//The first line may be written as the shortcut format var airlineCode = [String: String]()

Add new item

airlineCode["EVA Air"] = "BR"

//airlineCode = ["EVA Air": "BR"]

Reset the dictionary

airlineCode = [:]