> For the complete documentation index, see [llms.txt](https://yar999.gitbook.io/gopl-zh/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yar999.gitbook.io/gopl-zh/ch6.md).

# 方法

从90年代早期开始，面向对象编程(OOP)就成为了称霸工程界和教育界的编程范式，所以之后几乎所有大规模被应用的语言都包含了对OOP的支持，go语言也不例外。

尽管没有被大众所接受的明确的OOP的定义，从我们的理解来讲，一个对象其实也就是一个简单的值或者一个变量，在这个对象中会包含一些方法，而一个方法则是一个一个和特殊类型关联的函数。一个面向对象的程序会用方法来表达其属性和对应的操作，这样使用这个对象的用户就不需要直接去操作对象，而是借助方法来做这些事情。

在早些的章节中，我们已经使用了标准库提供的一些方法，比如time.Duration这个类型的Seconds方法：

```go
const day = 24 * time.Hour
fmt.Println(day.Seconds()) // "86400"
```

并且在2.5节中，我们定义了一个自己的方法，Celsius类型的String方法:

```go
func (c Celsius) String() string { return fmt.Sprintf("%g°C", c) }
```

在本章中，OOP编程的第一方面，我们会向你展示如何有效地定义和使用方法。我们会覆盖到OOP编程的两个关键点，封装和组合。


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