废话不多说了，直接给大家贴代码了。
var string = "Hello-Swift"//获取某个下标后一个下标对应的字符 char="e"//swift2.2//var char = string[startIndex.successor()]//swift3.0var char = string[string.index(after: startIndex)]//获取某个下标前一个下标对应的字符 char2 = "t"//swift2.2//var char2 = string[endIndex.predecessor()]//swift3.0var char2 = string[string.index(before: string.endIndex)]//通过范围获取字符串中的一个子串 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]//获取某个子串在父串中的范围//swift2.2//var range = string.rangeOfString("Hello")//swift3.0var range = string.range(of: "Hello")//追加字符串操作 此时string = "Hello-Swift! Hello-World"//swift2.2//string.appendContentsOf(" Hello-World")//swift3.0string.append(" Hello-World")//在指定位置插入一个字符 此时string = "Hello-Swift!~ Hello-World"//swift2.2//string.insert("~", atIndex: string.startIndex.advancedBy(12))//swift3.0string.insert("~", at: string.index(string.startIndex, offsetBy: 12))//在指定位置插入一组字符 此时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))//在指定范围替换一个字符串 此时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")//在指定位置删除一个字符 此时string = "Hi-Swift!~~~~ Hello-Worl"//swift2.2//string.removeAtIndex(string.endIndex.predecessor())//swift3.0string.remove(at: string.index(before:string.endIndex))//删除指定范围的字符 此时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"//全部转换为大写//swift2.2//string2 = string2.uppercaseString//swift3.0string2 = string2.uppercased()//全部转换为小写//swift2.2//string2 = string2.lowercaseString//swift3.0string2 = string2.lowercased()
需要注意，在Swift3.0中Range结构体被划分成了两种类型，Range和ClosedRange，分别用来描述左闭右开区间和闭区间，对应到运算符为0..<10和0...10。
从上面的示例代码中可以看出，String类型中的很多方法命名进行了Swift风格的简化，改动较大的一个点是关于下标index的改变，移除了两个Index下标移动的方法，使用String类型的index()方法来进行下标的移动操作，编程更加安全。
以上所述是小编给大家介绍的初探Swift3.0带来的变化汇总，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对脚本之家网站的支持！
