golang map的基本操作及定义方式

var a map[string]int
	a = make(map[string]int, 16)
	fmt.Printf("a = %#v \n", a)
	a["stu01"] = 1000

a := map[string]int{
		"stu01": 100,
		"stu03": 300,
		"stu02": 200,
	}
	fmt.Printf("a = %#v \n", a)

func test3() {
	var a map[string]int
	a = make(map[string]int, 16)
	fmt.Printf("a = %#v \n", a)
	a["stu01"] = 1000
	a["stu02"] = 2000
	var result int
	var ok bool
	var key string = "stu04"
	result, ok = a[key]
	if ok == false {
		fmt.Printf("key is %s is not exist\n", key)
	} else {
		fmt.Printf("key is %s = %d \n", key, result)
	}
}

func test4() {
	rand.Seed(time.Now().UnixNano())

	var a map[string]int
	a = make(map[string]int, 1024)
	for i := 0; i < 128; i++ {
		key := fmt.Sprintf("stu%d", i)
		value := rand.Intn(1000)
		a[key] = value
	}
	for key, value := range a {
		fmt.Printf("map[%s]=%d\n", key, value)
	}
}

func test5() {
	var a map[string]int
	a = make(map[string]int, 16)
	fmt.Printf("a = %#v \n", a)
	a["stu01"] = 1000
	a["stu02"] = 2000
	a["stu03"] = 3000
	fmt.Printf("a = %#v \n", a)
	delete(a, "stu02")
	fmt.Printf("DEL after a = %#v \n", a)
}

func test6() {
	var a map[string]int
	if a == nil {
		a = make(map[string]int, 16)
		a["stu01"] = 1000
		a["stu02"] = 2000
		a["stu03"] = 3000
		fmt.Printf("a = %#v \n", a)
		b := a
		b["stu01"] = 8888
		fmt.Printf("after modify a : %#v\n", a)
	}
}

func main() {
	rand.Seed(time.Now().UnixNano())
	var s []map[string]int
	s = make([]map[string]int, 5, 16)
	for index, value := range s {
		fmt.Printf("slice[%d] = %v \n", index, value)
	}
	fmt.Println()
	s[0] = make(map[string]int, 16)
	s[0]["stu01"] = 1000
	s[0]["stu02"] = 2000
	s[0]["stu03"] = 3000
	for index, value := range s {
		fmt.Printf("slice[%d] = %v \n", index, value)
	}
}