// 两个字符串均为空并等价。
var emptyString = ""               // 空字符串字面量
var anotherEmptyString = String()  // 初始化 String 实例

let wiseWords = "\"我是要成为海贼王的男人\" - 路飞"
// "我是要成为海贼王的男人" - 路飞
let dollarSign = "\x24"                // $,  Unicode 标量 U+0024
let blackHeart = "\u2665"              // ♥,  Unicode 标量 U+2665
let sparklingHeart = "\U0001F496"    // ????, Unicode 标量 U+1F496

//字符串拼接
var x = "x"
var y = "y"
var z = x + y
var m = z + "m"
var n = "n"
n += m

//使用\()完成字符串的插值
var result = "\(x)==\(y)==\(z)==\(m)==\(n)"
println(result)//结果:x==y==xy==xym==nxym

//字符串与字符拼接
let s1 = "hello"
let c1: Character = "!"
let plus1 = s1 + c1        // 等于 "hello!"
let plus2 = c1 + s1        // 等于 "!hello"

var myString = "This is a string"

for character in myString{
   println(character)
}

var myString = "Here is my string, lets count the characters!"
println(myString.characters.count)

var check1:String = "Swift is good!"
var check2:String = "Swift is good!"

//字符串是否相等
if check1 == check2 {
    println("check1 = check2")
} else {
    println("check1 != check2")
}

//是否包含前缀
var preCheck = "Swift"
if check1.hasPrefix(preCheck) {
    println("包含前缀")
}

//是否包含后缀
var sufCheck = "good!"
if check1.hasSuffix(sufCheck) {
    println("包含后缀")
}

let myString = "Wait a moment, please."
let newString = myString.uppercaseString
//The string is now "WAIT A MOMENT, PLEASE."

let myString = "Wait a moment, please."
let newString = myString.lowercaseString
// The string is now "wait a moment, please."

var myString = "This is a string test"
if myString.rangeOfString("string") {
    println("exists")
}

//截取字符串的标识位从1开始计数
let myString = "ABCDEFGHI"

//1.从目标标识位后一个字符开始截取余下的字符串
let mySubstring = (myString.substringFromIndex(2))
println(mySubstring)    // "CDEFGHI"

//2.从第一个字符截取到目标标识位
let mySubstring2 = (myString.substringToIndex(4))
println(mySubstring2)   // "ABCD"

var myString = "    Let's trim the whitespace    "
var newString = myString.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceCharacterSet())

//单一分隔符:只有一种分割符
var myString = "Berlin, Paris, New York, San Francisco"

//1.隐式定义字符串数组
var myArray = myString.componentsSeparatedByString(",")

//2.显示定义字符串数组
var myArray2 : String[] = myString.componentsSeparatedByString(", ")

for em in myArray2 {
    print(em)   //Berlin Paris New York San
}


//多重分割符:有2个或两个以上分隔符
var myString2 = "One-Two-Three-1 2 3"

var array2:String[] = myString2.componentsSeparatedByCharactersInSet(NSCharacterSet (charactersInString: "- "))
//["One", "Two", "Three", "1", "2", "3"]

let myString = "String to encode"
let string: NSString = myString
let data = string.dataUsingEncoding(NSUTF8StringEncoding)