Swift

//: Playground - noun: a place where people can play

import Foundation

var str = "Hello, playground"
str.capitalizedString   // 字符串中所有单词首字母大写, 不改变str本身的值
str
str += ", hello, rinpe chan"
str.capitalizedString
str.uppercaseString     // 全大写
str.lowercaseString     // 全小写

// trim
var str2 = "   hi    ?!@"
str2.stringByTrimmingCharactersInSet(NSCharacterSet(charactersInString: " !?@"))     // 切除字符串中的字符

// split
var str3 = "welcome to Shantou"
str3.componentsSeparatedByString(" ")   // 分割

// 分割更复杂的字符串
var str4 = "rinpe, bobo! how-are-u?"
str4.componentsSeparatedByCharactersInSet(NSCharacterSet(charactersInString: " !-?"))

// join
var str5 = "-"
["1", "2", "3"].joinWithSeparator(str5)