英文:
copy data from one golang slice struct to another slice strcut
问题
package main
import (
"encoding/json"
"fmt"
)
type Machine struct {
hostname string
Ip string
Name string
}
type Host struct {
HostName string json:"host_name"
Vars Var json:"vars"
}
type Service struct {
ServiceName string json:"service_name"
Required bool json:"required"
Hosts []Host json:"hosts"
Vars Var json:"vars"
}
func main() {
machineInfo := [{"dns":"1.1.1.1.eu-south-1.compute.amazonaws.com","ip":"1.1.1.1","name":"Machine-1"},{"dns":"1.1.1.2.eu-south-1.compute.amazonaws.com","ip":"1.1.1.2","name":"Machine-2"}]
var machines []Machinevar mService Servicejson.Unmarshal([]byte(machineInfo), &machines)for i := range machines {host := Host{HostName: machines[i].hostname,Vars: Var{}, // You need to define the Var struct}mService.Hosts = append(mService.Hosts, host)}fmt.Printf("Machines: %v", mService)data, _ := json.Marshal(mService)fmt.Println(string(data))
}
英文:
Hi I have json data which I Unmarshal tomachines slice . Now I am looking to copy/append each hostname from machines slice struct to service Struct []hosts . I have tried few methods but struggling to iterate over []hosts slice in service struct .
Just wondering what is the best way to copy the value from one slice struct to another slice value inside some other struct.
package mainimport ("encoding/json""fmt")type Machine struct {hostname stringIp stringName string}type Host struct {HostName string `json:"host_name"`Vars Var `json:"vars"`}type Service struct {ServiceName string `json:"service_name"`Required bool `json:"required"`Hosts []Host `json:"hosts"`Vars Var `json:"vars"`}func main() {machineInfo := `[{"dns":"1.1.1.1.eu-south-1.compute.amazonaws.com","ip":"1.1.1.1","name":"Machine-1"},{"dns":"1.1.1.2.eu-south-1.compute.amazonaws.com","ip":"1.1.1.2","name":"Machine-2"}]`var machines []Machinevar mService *Service//convert the json to byts slice and thenjson.Unmarshal([]byte(machineInfo), &machines)//Data is now add to the structsfor i, _ := range machines {mService.Hosts = append(mService.Hosts, machines[i].hostname)}fmt.Printf("Machines : %v", mService)data, _ := json.Marshal(mService)fmt.Println(string(data))}
答案1
得分: 2
让我们从头开始：
通过将主机名字段大写来导出它。JSON解码器会忽略意外的字段。此外，添加一个标签以使该字段与文档匹配：
type Machine struct {Hostname string `json:"name"`Ip stringName string}
声明mServices为一个值，以避免空指针恐慌：
var mService Service
使用复合字面表达式创建一个主机，以便将其附加到切片中：
mService.Hosts = append(mService.Hosts, Host{HostName: machines[i].Hostname})
https://go.dev/play/p/nTBVwM3l9Iw
英文:
Let's take it from the top:
Export the hostname field by capitalizing it. The JSON decoder ignores unexpected fields. Also, add a tag so the field matches the document:
type Machine struct {Hostname string `json:"name"`Ip stringName string}
Declare mServices as a value to avoid nil pointer panic:
var mService Service
Use a composite literal expression to create a host for append to the slice:
mService.Hosts = append(mService.Hosts, Host{HostName: machines[i].Hostname})
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