小编Jum*_*nyi的帖子

我正在学习使用地图的地图。在以下示例中，有三个嵌套映射。

package main

import (
    "fmt"
)

func main() {

    var data = map[string]map[string]map[string]string{}

    data["Date_1"] = map[string]map[string]string{}
    data["Date_1"] = make(map[string]map[string]string, 1)
    data["Date_1"] = make(map[string]map[string]string, 0)

    data["Date_1"]["Sistem_A"] = map[string]string{}
    data["Date_1"]["Sistem_A"] = make(map[string]string, 0)
    data["Date_1"]["Sistem_A"] = make(map[string]string, 0)

    data["Date_1"]["Sistem_A"]["command_1"] = "white"
    data["Date_1"]["Sistem_A"]["command_2"] = "blue"
    data["Date_1"]["Sistem_A"]["command_3"] = "red"

    fmt.Println("data: ", data)
}

输出

data:  map[Date_1:map[Sistem_A:map[command_1:white command_2:blue command_3:red]]]

问题是，如果我想在一个步骤中添加值？？我会感到恐慌：分配到 nil 映射中的条目。

package main

import (
    "fmt"
)

func main() {

    var data = map[string]map[string]map[string]string{}

    data["Date_1"] = map[string]map[string]string{}
    data["Date_1"] = make(map[string]map[string]string, 0)
    data["Date_1"] = make(map[string]map[string]string, …