Swift学习笔记-字典Dictionary_app

概述//字典 //声明 //1.泛型语法声明 var myDict : Dictionary<String,String> //2.使用简化语法声明 var dictText : [String:Int] var dictText1 : [String:String] //赋值

//字典        //声明        //1.泛型语法声明        @H_301_8@var myDict : Dictionary<String,String>        //2.使用简化语法声明        @H_301_8@var dictText : [String:Int]        @H_301_8@var dictText1 : [String:String]        //赋值        //1.创建一个字典结构体，使用默认的参数        myDict = Dictionary<String,String>()        println(myDict)//[:]        dictText = Dictionary<String,Int>(minimumCapacity: 5)        println(dictText)        //2.使用简化语法创建字典        dictText1 = ["high":"20","fat":"110"]        println(dictText1)//[fat: 110,high: 20]        //创建不包含任何key-value对的字典        @H_301_8@var emptyDic : [String:Double] = [:]        //isEmpty属性可判断数组，字典是否不包含任何元素        println(emptyDic.isEmpty) //true        @H_301_8@var em : [String:String]        em = Dictionary()        println(em.isEmpty)        //字典的使用        @H_301_8@var high = dictText1["high"]        println(high)//Optional("20")        //访问不存在的key返回nil       @H_301_8@var tro = dictText1["tro"]        println("\(tro)")//nil        //修改指定的key对应的value        dictText1["fat"] = "200"        println(dictText1)//[fat: 200,high: 20]        //如果key不存在，则添加        dictText1["pressure"] = "112"        println(dictText1)//[fat: 200,high: 20,pressure: 112]        //如果需要返回key对应的value需要加“！”强制解析        @H_301_8@var englis : String? = dictText1["high"]        @H_301_8@if englis != nil        {            println(englis!)        }@H_301_8@var result = dictText1.updateValue("289",forKey: "fat")        println("result is \(result)")//result is Optional("200")        println(dictText1)//[fat: 289,pressure: 112]        /** for in遍历字典 */        @H_301_8@var seasons = ["a":"测试","b":"summer","c":"autumn"]        /** * b:summer a:测试 c:autumn */        @H_301_8@for (season,desc) in seasons        {            println("\(season):\(desc)")        }        /** 单独使用字典的keys和values */        @H_301_8@var keys = Array(seasons.keys)        @H_301_8@var valuess  = Array(seasons.values)        println("\(keys)....\(valuess)")//[b,a,c]....[summer,测试,autumn]        //删除        seasons.removeValueForKey("d")        /** [b: summer,a: 测试,c: autumn] */        println(seasons)        seasons.removeValueForKey("c")        //[b: summer,a: 测试]        println(seasons)        //通过将value赋值为nil来删除        seasons["b"] = nil        println(seasons)//[a: 测试]