学步园

import Cocoa

//打印信息
println("Hello, Swift")


//变量与常量
//使用var声明变量，let声明常量

var myVariable = 42
myVariable = 50

let myConstant = 42

//类型推导(Type Inference)
let explicitDouble : Double = 70

//不支持隐式类型转换（Implicitly casting）,所以下面的代码需要显式类型转换（Explicitly castrng）,也就是说必须进行强制类型转换
let label = "The width is "
let width = 94
let widthLabel = label + String(width)

//字符串格式化，使用\(item)的形式进行字符串格式化：
let apples = 3
let oranges = 5
let appleSummary = "I have \(apples) apples."
let fruitSummary = "I have \(apples + oranges) pieces of fruit."

//数组和字典，使用[]声明数组（array）和字典(dictionary)
var shoppingList = ["catfish", "water", "tulips", "blue paint"]
shoppingList[1] = "bottle of water"

var occupations = [
    "Malcolm":"Captain",
    "Kaylee":"Mechanic",
]
occupations["Jayne"] = "Public Relations"

//一般使用初始化器（initializer）语法创建空数组和空字典
let emptyArray = String[]()
let emptyDictionary = Dictionary<String, Float>()