var string = "Hello-Swift"//獲取某個(gè)下標(biāo)后一個(gè)下標(biāo)對應(yīng)的字符 char="e"//swift2.2//var char = string[startIndex.successor()]//swift3.0var char = string[string.index(after: startIndex)]//獲取某個(gè)下標(biāo)前一個(gè)下標(biāo)對應(yīng)的字符 char2 = "t"//swift2.2//var char2 = string[endIndex.predecessor()]//swift3.0var char2 = string[string.index(before: string.endIndex)]//通過范圍獲取字符串中的一個(gè)子串 Hello//swift2.2//var subString = string[startIndex...startIndex.advancedBy(4)]//swift3.0var subString = string[startIndex...string.index(startIndex, offsetBy: 4)]//swift2.2//var subString2 = string[endIndex.advancedBy(-5)...endIndex.predecessor()]//swift3.0var subString2 = string[string.index(endIndex, offsetBy: -5)..<endIndex]//獲取某個(gè)子串在父串中的范圍//swift2.2//var range = string.rangeOfString("Hello")//swift3.0var range = string.range(of: "Hello")//追加字符串操作 此時(shí)string = "Hello-Swift! Hello-World"//swift2.2//string.appendContentsOf(" Hello-World")//swift3.0string.append(" Hello-World")//在指定位置插入一個(gè)字符 此時(shí)string = "Hello-Swift!~ Hello-World"//swift2.2//string.insert("~", atIndex: string.startIndex.advancedBy(12))//swift3.0string.insert("~", at: string.index(string.startIndex, offsetBy: 12))//在指定位置插入一組字符 此時(shí)string = "Hello-Swift!~~~~ Hello-World"//swift2.2//string.insertContentsOf(["~","~","~"], at: string.startIndex.advancedBy(12))//swift3.0string.insert(contentsOf: ["~","~","~"], at: string.index(string.startIndex, offsetBy: 12))//在指定范圍替換一個(gè)字符串 此時(shí)string = "Hi-Swift!~~~~ Hello-World"//swift2.2//string.replaceRange(string.startIndex...string.startIndex.advancedBy(4), with: "Hi")//swift3.0string.replaceSubrange(string.startIndex...string.index(string.startIndex, offsetBy: 4), with: "Hi")//在指定位置刪除一個(gè)字符 此時(shí)string = "Hi-Swift!~~~~ Hello-Worl"//swift2.2//string.removeAtIndex(string.endIndex.predecessor())//swift3.0string.remove(at: string.index(before:string.endIndex))//刪除指定范圍的字符 此時(shí)string = "Swift!~~~~ Hello-Worl"//swift2.2//string.removeRange(string.startIndex...string.startIndex.advancedBy(2))//swift3.0string.removeSubrange(string.startIndex...string.index(string.startIndex, offsetBy: 2))var string2 = "My name is Jaki"//全部轉(zhuǎn)換為大寫//swift2.2//string2 = string2.uppercaseString//swift3.0string2 = string2.uppercased()//全部轉(zhuǎn)換為小寫//swift2.2//string2 = string2.lowercaseString//swift3.0string2 = string2.lowercased()