在循环内追加会重复 Golang 中的最后一个值

Question

当尝试在 go 中追加迭代的值时，函数将最后一次迭代追加 4 次。例如，我正在尝试将包含网卡数据的字符串解析为映射，并且在迭代时仅附加最后一个：

这是带有代码的 playground link： https://go.dev/play/p/mKtFvK36PMn

package main

import (
    "fmt"
    "strings"
)

type Foo struct {
    val int
}

func main() {

    NetworkJson := "4 NIC(s) Installed.,[01]: Realtek PCIe GbE Family Controller,      Connection Name: Ethernet,      DHCP Enabled:    Yes,      DHCP Server:     10.101.10.13,      IP address(es),      [01]: 10.1.2.62,[02]: VirtualBox Host-Only Ethernet Adapter,      Connection Name: VirtualBox Host-Only Network,      DHCP Enabled:    No,      IP address(es),      [01]: 192.168.56.1,      [02]: fe80::4c17:978a:2c91:8e27,[03]: VMware Virtual Ethernet Adapter for VMnet1,      Connection Name: VMware Network Adapter VMnet1,      DHCP Enabled:    Yes,      DHCP Server:     192.168.146.254,      IP address(es),      [01]: 192.168.146.1,      [02]: fe80::88b4:d443:2ab8:59b5,[04]: VMware Virtual Ethernet Adapter for VMnet8,      Connection Name: VMware Network Adapter VMnet8,      DHCP Enabled:    Yes,      DHCP Server:     192.168.128.254,      IP address(es),      [01]: 192.168.128.1,      [02]: fe80::a40d:e64:fa9f:e82f"
    var IPs []string
    var Data []string
    var IPMap = make(map[string]string)
    var CardMap = make(map[string]interface{})
    var CardIP = make(map[string][]map[string]string)
    var NetCard = make(map[string][]interface{})

    // Faz loop entre as placas de rede
    for _, Cards := range strings.Split(string(NetworkJson), ",[") {

        // Faz loop entre os dados de cada placa
        for _, CardData := range strings.Split(string(Cards), ",") {

            // Verifica se dado inicia com espaço em branco
            if strings.HasPrefix(CardData, " ") {

                // Verifica se dado sem o espaço em branco começa com [
                if strings.HasPrefix(strings.TrimSpace(CardData), "[") {

                    // Pega IPS
                    IPs = strings.Split(strings.TrimSpace(string(CardData)), ": ")
                    IPMap[string(IPs[0])] = strings.TrimSpace(string(IPs[1]))

                    // Se não iniciar com [ verifica se contém :
                } else if strings.Contains(CardData, ":") {

                    // Pega restante dos dados
                    Data = strings.Split(strings.TrimSpace(string(CardData)), ":")
                    CardMap[Data[0]] = strings.TrimSpace(Data[1])

                }

            }

        }

        if strings.Contains(Cards, "]") {

            // Aloca dados
            CardMap["Card Name"] = string(strings.SplitN(string(Cards), ",", 2)[0])[5:]
            CardIP["IP Adress(es)"] = append(CardIP["IP Adress(es)"], IPMap)
            CardMap["IP Adress(es)"] = CardIP["IP Adress(es)"]
            CardIP["IP Adress(es)"] = CardIP["IP Adress(es)"][:0]

            NetCard["Cards"] = append(NetCard["Cards"], CardMap)
            fmt.Println(CardMap)

        }
        fmt.Println(NetCard["Cards"])
    }
}

Answer 1

您正在将所有内容存储到同一个地图变量 CardMap 中，并且您使用的是单一键“Card Name”。 append(NetCard["Cards"], CardMap) 不会执行 CardMap 的 deep 副本，只会附加一个浅表副本，因此每次迭代都会更新浅表副本的数据。你的其他变量也有同样的问题。

将变量声明移动到主循环中：

var NetCard = make(map[string][]interface{})

// Faz loop entre as placas de rede
for _, Cards := range strings.Split(string(NetworkJson), ",[") {

    var IPs []string
    var Data []string
    var IPMap = make(map[string]string)
    var CardMap = make(map[string]interface{})
    var CardIP = make(map[string][]map[string]string)

    // Faz loop entre os dados de cada placa
    for _, CardData := range strings.Split(string(Cards), ",") {
        // ...

https://go.dev/play/p/VE_VWOsvsna

在循环内追加会重复 Golang 中的最后一个值

Appending inside a loop repeats the last value in Golang

loops

append

go