80 lines
1.6 KiB
Markdown
80 lines
1.6 KiB
Markdown
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---
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title: Go Maps
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localeTitle: 去地图
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---
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## 去地图
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地图，在其他语言中称为_字典_ ，将键“映射”到值。 地图声明如下：
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```go
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var m map[Key]Value
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```
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此地图没有按键，也无法添加任何按键。 要创建地图，请使用`make`函数：
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```go
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m = make(map[Key]Value)
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```
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任何东西都可以用作键或值。
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### 修改地图
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以下是地图的一些常见操作。
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#### 插入/更改元素
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在地图`m`创建或更改元素`foo` ：
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```go
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m["foo"] = bar
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```
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#### 获得元素
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在map `m`获取带有键`foo`元素：
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```go
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element = m["foo"]
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```
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#### 删除元素
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在地图`m`使用键`foo`删除元素：
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```go
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delete(m, "foo")
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```
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#### 检查是否已使用密钥
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检查地图`m`是否使用了密钥`foo` ：
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```go
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element, ok = m["foo"]
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```
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如果`ok`为`true` ，则使用密钥， `element`将值保存在`m["foo"]` 。 如果`ok`为`false` ，则表示未使用该键，且该`element`保持其零值。
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### 映射文字
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您可以直接创建地图文字：
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```go
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var m = map[string]bool{
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"Go": true,
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"JavaScript":false,
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}
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m["Go"] // true
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m["JavaScript"] = true // Set Javascript to true
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delete(m, "JavaScript") // Delete "JavaScript" key and value
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language, ok = m["C++"] // ok is false, language is bool's zero-value (false)
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```
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#### 更多信息：
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* [围棋之旅](https://tour.golang.org/moretypes/19)
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* [以身作则](https://gobyexample.com/maps)
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* [Golang Book](https://www.golang-book.com/books/intro/6#section3)
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* [Go编程语言规范](https://golang.org/ref/spec#Making_slices_maps_and_channels)
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