4.Array_Slice_Map.go

package main

import (
	"fmt"
	"sort"
)

func main() {

	//数组, 不能增删,只能改查
	var nameList = [3]string{"小红", "小黄", "小绿"}
	fmt.Println(nameList)
	fmt.Println(nameList[0])
	fmt.Println(nameList[len(nameList)-1])

	//切片或列表，可以增删改查
	var colorList []string
	colorList = append(colorList, "blue")
	colorList = append(colorList, "red")
	fmt.Println(colorList)

	var nullList []string //定义为空
	fmt.Println(nullList)
	fmt.Println(nullList == nil) //nil是go语言的null

	var ageList = make([]int, 3) //用make初始化, 创建指定容量的slice, 用0来填充未赋值的位置
	ageList = append(ageList, 1)
	fmt.Println(ageList)

	//切片切数组
	var arrayTest = [6]int{1, 2, 3, 4, 5, 6}
	slice1 := arrayTest[:]
	slice2 := arrayTest[:2]
	fmt.Println(slice1)
	fmt.Println(slice2)

	//排序操作
	var arrayTest2 = []int{7, 3, 3, 8, 5, 6}
	sort.Ints(arrayTest2) //升序
	fmt.Println(arrayTest2)
	sort.Sort(sort.Reverse(sort.IntSlice(arrayTest2))) //降序
	fmt.Println(arrayTest2)

	//map
	var userMap = map[int]string{
		1: "yuki",
		2: "Jerry",
	}
	fmt.Println(userMap)
	fmt.Println(userMap[1])
	fmt.Printf("%#v\n", userMap[4]) //试试超越下标的，获取空字符串

	var userValue = userMap[1]
	fmt.Println(userValue)
	var userValue2, boolValue2 = userMap[2]
	fmt.Println(userValue2, boolValue2) //两个变量去接Map的Value，第二个会接出来一个bool值
	var userValue3, boolValue3 = userMap[10]
	fmt.Printf("%#v,%v\n", userValue3, boolValue3) //两个变量去接Map的Value，第二个会接出来一个bool值

	var stringMap = map[string]string{
		"wuhu":      "yuki",
		"guangzhou": "Jerry",
	}
	fmt.Println(stringMap)
	fmt.Println(stringMap["wuhu"])

	stringMap["wuhu"] = "xie"
	fmt.Println(stringMap)

	delete(stringMap, "wuhu")
	fmt.Println(stringMap)

}