Swift4.0字典的常用详解

//创建字典的方法 var someDict = [Int:String]() someDict.count //定义一个key为字符串value也为字符串的字典 //这种的之所以没有按照顺序排列 因为不是数字的，是字符串的排列方式 var someDict1 : [String:String]=["1":"2222","2":"44444"] someDict1 //访问字典的值 var DicValue1 = someDict1["2"]

//修改字典的值 var someDict2:[Int:String] = [1:"One", 2:"Two", 3:"Three"]

var oldVal = someDict2.updateValue("One 新的值", forKey: 1) someDict2 someDict1["2"]="nihaoa" someDict1 //移除字典的值 var removedValue = someDict2.removeValue(forKey:2)

someDict2

var removedValue1 = someDict1.removeValue(forKey: "1") someDict1

//字典的增加 var addValue = someDict1.updateValue("33333", forKey: "4") someDict1 //遍历字典 for (key,value) in someDict1 {          print(key+"==="+value) } for (key, value) in someDict2.enumerated() {     print("键是\(key)=====值是\(value)") }

//字典转数组 let keyArray = [String](someDict1.keys); let valueArray = [String](someDict1.values); //字典的长度 someDict2.count

//判断字典是否为空 let bool1 = someDict2.isEmpty print(bool1)