打印输出

@H_403_3@println("hello,world")

末尾不需要加分号

定义变量用var，常量用let

@H_403_3@var myVariable = 42 let myConstant = 42

变量和常量的类型应该和我们想要的类型一致，编译器可以帮助我们推断类型，我们也可以显示指定类型

@H_403_3@let explicitDouble: Double = 70

显示转换类型

@H_403_3@let width = 94 let widthLable = lable + String(width)

在字符串中打印数值，在要格式化的数值前加”()”

@H_403_3@let apples = 3 let oranges = 5 let appleSummary = "I have \(apples) apples." let fruitSummary = "I have \(apples + oranges) pieces of fruit."

创建数组和字典

@H_403_3@//数组 var shoppingList = ["catfish","water","tulips","blue paint"] shoppingList[1] = "bottle of water" //字典 var occupations = [ "Malcolm": "Captain","Kaylee": "Mechanic",] occupations["Jayne"] = "Public Relations"

创建空数组和字典

@H_403_3@let emptyArray = String[]() let emptyDictionary = Dictionary<String,Float>()