Go语言的map以及sort

通过这个例子了解map的使用。

Go语言程序：

// map project main.go
package main

import (
	"fmt"
	"sort"
)

func main() {

	var countryCapitalMap map[string]string
	/* 创建集合 */
	countryCapitalMap = make(map[string]string)

	/* map 插入 key-value 对，各个国家对应的首都 */
	countryCapitalMap["France"] = "Paris"
	countryCapitalMap["Italy"] = "Rome"
	countryCapitalMap["Japan"] = "Tokyo"
	countryCapitalMap["India"] = "New Delhi"
	countryCapitalMap["China"] = "Beijing"

	fmt.Println("Original:")
	/* 使用 key 输出 map 值 */
	for country := range countryCapitalMap {
		fmt.Println("Capital of", country, "is", countryCapitalMap[country])
	}
	fmt.Println("")

	/* map 删除 key-value 对 */
	delete(countryCapitalMap, "India")
	fmt.Println("After deletion:")
	/* 使用 key 输出 map 值 */
	for country := range countryCapitalMap {
		fmt.Println("Capital of", country, "is", countryCapitalMap[country])
	}
	fmt.Println("")

	/* 映射反转 */
	capitalCountryMap := make(map[string]string, len(countryCapitalMap))
	for country, capital := range countryCapitalMap {
		capitalCountryMap[capital] = country
	}
	fmt.Println("After the reversal:")
	for capital := range capitalCountryMap {
		fmt.Println("Country of", capital, "is", capitalCountryMap[capital])
	}
	fmt.Println("")

	/* 查看元素在集合中是否存在 */
	captial, ok := countryCapitalMap["United States"]
	/* 如果 ok 是 true, 则存在，否则不存在 */
	if ok {
		fmt.Println("Capital of United States is", captial)
	} else {
		fmt.Println("Capital of United States is not present")
	}
	fmt.Println("")

	/* 排序输出 */
	var keys []string
	for k := range countryCapitalMap {
		keys = append(keys, k)
	}
	sort.Strings(keys)
	for _, k := range keys {
		fmt.Println("Key:", k, "Value:", countryCapitalMap[k])
	}
}

 

程序运行结果：

Original:
Capital of France is Paris
Capital of Italy is Rome
Capital of Japan is Tokyo
Capital of India is New Delhi
Capital of China is Beijing

After deletion:
Capital of France is Paris
Capital of Italy is Rome
Capital of Japan is Tokyo
Capital of China is Beijing

After the reversal:
Country of Paris is France
Country of Rome is Italy
Country of Tokyo is Japan
Country of Beijing is China

Capital of United States is not present

Key: China Value: Beijing
Key: France Value: Paris
Key: Italy Value: Rome
Key: Japan Value: Tokyo

程序说明：

1.map似乎可以直接使用

2.排序可以使用sort包

3.map是无序的需要另外定义一个数组来排序

参考链接：

1.Ubuntu安装Go语言环境

2.Ubuntu构筑LiteIDE的Go语言开发环境