## String and Characters
Swift’s String type is a value type. If you create a new String value, that String value is copied when it is passed to a function or method, or when it is assigned to a constant or variable.
String判斷是否包含某前綴或后綴的方法：hasPrefix，hasSuffix
String怎么隨機取其中一個字符？
- About Swift
- The Basics
- Basic Operators
- String and Characters
- Collection Types
- Control Flow
- Functions
- Closures
- Enumerations
- Classes and Structures
- Properties
- Methods
- Subscripts
- Inheritance
- Initialization
- Deinitialization
- Automatic Reference Counting
- Optional Chaining
- Type Casting
- Nested Types
- Extensions
- Protocols
- Generics
- Advanced Operators
- A Swift Tour