Swift语言精要 - Dictionary(字典)

字典以键值对的形式存储数据。

键不能重复，但是值可以重复。

基本语法用例：

var states : Dictionary<String, String> = ["CA" : "California"]var states : [String : String] = ["CA" : "California"]

也可以使用类型推断的方式：

var states = ["CA" : "California"]var states = ["CA" : "California", "NV" : "Nevada", "OR": "Oregon", "AZ" : "Arizona"]

修改键值：

states["NV"] = "Nevada"

或者

states.updateValue("State of Nevada", forKey: "NV")

访问键值：

let value = states["NV"]

删除键值：

states["TX"] = nil// 或者states.removeValueForKey("TX")

遍历键值对：

// iterate keys and valuesfor (key, value) in states {    print("State name = \(value), abbreviation = \(key)")}// iterate keysfor abbreviation in states.keys {    print("Abbreviation = \(abbreviation)")}// iterate valuesfor name in states.values {    print("Name = \(name)")}