Swifit基本数据类型（三）

////  main.swift//  Swifit基本数据类型（三）////  Created by Goddog on 15/6/23.//  Copyright (c) 2015年 Goddog. All rights reserved.//import Foundation//MARK: - 字符串和字符//MARK:   - -字符//Swift通过Character类型代表单个字符var s : Character = "好"var qu1 = "\""var qu2 = "\u{22}"println("s是：\(s),qu1是：\(qu1),qu2是:\(qu2)")//MARK: - -字符串//Swift通过String类型代表字符串var str1 = "Swift"var str2 : String = "Swift-"var str3 = String()  //创建空字符串var str4 = String(count: 5, repeatedValue: Character("v"))  //创建具有多个重复的字符串println("str1:\(str1),   str2:\(str2),   str3:\(str3),   str4:\(str4)")println("str3是否为空：\(str3.isEmpty)")   //判断是否为空//字符串连接let aa = "i like"var info = aa + "Swift"println(info)//MARK: - Swift与Foundation进行无缝桥接之String//定义一个NSString类型的变量，可以直接将Swift的字符串赋值给abc变量var abc : NSString = "Swift"var subStr = abc.substringWithRange(NSMakeRange(1, 3))println(subStr)/**    注意：Foundation框架中的NSString是一个类，引用类型(指针类型)         Swift的String是一个结构体，值类型*///字符串的可变性//在OC中字符串有NSString和NSMutableString，但是Swift只用String，用var可变和let不可变来区别var a1 = "Swift"a1 += "is a good programming language"println(a1)a1.removeAll(keepCapacity: false)   //清空//不可变let bb = "Java"//字符串的基本操作let nums = "abcdefg"println("总数：\(countElements(nums))")for num in nums{    println(num)}//字符串比较//字符串相等用==进行判断var st1 = "Swift"var st2 = String()var st3 = st1 + st2println(st3)var hasSwiftPrefix : Bool = st1.hasPrefix("Sw")println("st1是否以Sw开头:\(hasSwiftPrefix)")var hasOrgSuffix : Bool = st1.hasSuffix("ft")println("st1是否以ft结尾：\(hasOrgSuffix)")//获取字符串中字符的Unicode编码let cn = "Java"for codeUnit in cn.utf8{    println("获取字符串中字符的Unicode编码:\(codeUnit)")}println("Hello, World!")