我正在学习使用 map 的 map 。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,如果我想在一步中添加值,我会出现 panic :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, 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"
data["Date_2"]["Sistem_A"]["command_5"] = "violet"
fmt.Println("data: ", data)
}
输出panic: assignment to entry in nil map
在这一点上,指导信息非常少。你可以帮帮我吗?谢谢你。
最佳答案
是这里:
data["Date_2"]["Sistem_A"]["command_5"] = "violet"
表达式 data["Date_2"]
将返回一个 nil-map。它从未被初始化,因此寻找索引 ["Sistem_A"]
panic 。首先初始化 map : data["Date_2"]=make(map[string]map[string]string)
data["Date_2"]["Sistem_A"]=make(map[string]string)
data["Date_2"]["Sistem_A"]["command_5"] = "violet"
关于go - 如何将数据添加到 Golang 中的 map map ?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/64128440/