import Foundationprintln("Hello, World!");var v1 = 1;var v2 = 2;println(" v1 is \(v1)  v2 is \(v2)");var v3 = v1 + v2;println("v3 is \(v3)");//字符转换var v4 : Double = Double(v3) + 3.14;println("v4 is \(v4)");var v5 = "hello"let v6 = "world"println(v5 + " " + v6);//声明仅仅读类型变量let v7 = 3.1415;println("v7 is " + String(v7));var arr = [1,2,4,6];println("arr index 1 is \(arr[1])");//声明字典var airports: Dictionary
     
       = ["TYO": "Tokyo", "DUB": "Dublin"];var v8 = "10";//字符串是否为空if v8.isEmpty{    println("v8 is true");}//遍历字符串for character in "ddd1ew?"{    println("char is " + character)}//字符串长度计算let unusualMenagerie = "Koala ??
     

??, Snail ????, Penguin ?

???

, Dromedary ??

?

?

" println("unusualMenagerie has \(countElements(unusualMenagerie)) characters") var var9 = countElements(unusualMenagerie) println("var9 lenght is \(var9)") //比較字符串 let quotation = "We're a lot alike, you and I." let sameQuotation = "We're a lot alike, you and I." if quotation == sameQuotation { println("These two strings are considered equal") } //大写和小写转换 let normal = "Could you help me, please?" let shouty = normal.uppercaseString // shouty 值为 "COULD YOU HELP ME, PLEASE?

" let whispered = normal.lowercaseString // whispered 值为 "could you help me, please?" //String 转换 int var i :Int = "1".toInt()! println("\(i)")