Swift-字符串

////  main.swift//  BasicOperatorsDemo////  Created by 程磊 on 15/5/23.//  Copyright (c) 2015年 chenglei. All rights reserved.//import Foundation//字符串//Swift中的字符串不是指针，而是实际的值let someString = "ABC"var someStr = "ABC"//字符串常量可以包括下面这些特殊字符/*    空字符\0,反斜杠\,制表符\t,换行符\n,回车符\r,双引号\"和单引号\'    单字节Unicode字符，\xnn，其中nn是两个十六进制数    双字节Unicode字符，\unnnn，其中nnnn是四个十六进制数    四字节Unicode字符，\Unnnnnnnn，其中nnnnnnnn是八个十六进制数*///初始化空的字符串var emptyString = "";var emptyString2 = String();var char:Character = "a";emptyString2.append(char);//追加字符//检查字符串是否为空if emptyString.isEmpty {    println("字符串为空")}//追加字符串,直接用加号println(emptyString+emptyString2);//判断两个字符串是否相同，直接用==即可判断if emptyString == emptyString2 {    println("相同");}let meals = ["青菜：芹菜","青菜：胡萝卜","肉菜：鱼","肉菜：牛肉"];for meal in meals {    if meal.hasPrefix("青菜"){        println("前缀是青菜的\(meal)");    } else if meal.hasSuffix("肉") {        println("后缀是肉的\(meal)");    }}//字符计数()   count()let constStr = "cheng lei"println("constStr count is \(count(constStr))");//通过count返回的字符数量并不总是跟OC中NSSting的length相同，因为NSSting的length属性是基于UTF-16编码的数目，而count是基于Unicodelet normal = "hello, my name is bielian";let upper = normal.uppercaseString;let lower = normal.lowercaseString;println("normal = \(normal)");println("upper = \(upper)");println("lower = \(lower)");