How to parse json object and print particular value [duplicate] - arrays

Question

This question already has answers here:
JSON single value parsing
(2 answers)
Closed 2 years ago.
I have json object that consists sub object of array. how can I print particular sub object in json.
here is my code
package main
import (
"encoding/json"
"fmt"
)
func main() {
//Simple Employee JSON which we will parse
empArray := `{"meta":[
{
"id": 1,
"name": "Mr. Boss",
"department": "",
"designation": "Director"
},
{
"id": 11,
"name": "Irshad",
"department": "IT",
"designation": "Product Manager"
},
{
"id": 12,
"name": "Pankaj",
"department": "IT",
"designation": "Team Lead"
}
]}`
// Declared an empty interface of type Array
var results []map[string]interface{}
// Unmarshal or Decode the JSON to the interface.
json.Unmarshal([]byte(empArray['meta']), &results)
fmt.Println(results)
}
I'm getting below error while doing soo..
./test.go:35:23: cannot convert empArray['\u0000'] (type byte) to type []byte
./test.go:35:33: invalid character literal (more than one character)
with in the empArray array object, I wanted to print meta object that consists array of employees. Please help me to accomplish this.

Answer 1

You are almost there. Parse the entire document and then pick out the part you want.
var results map[string][]interface{}
json.Unmarshal([]byte(empArray), &results)
fmt.Println(results["meta"])

Answer 2

You should use custom structs:
type Employee struct {
ID int `json:"id"`
Name string `json:"name"`
Department string `json:"department"`
Designation string `json:"designation"`
}
type Employees struct {
Meta []Employee `json:"meta"`
}
When you try to unmarshal the provided string into a Employees var it will read the annotations and know where to place each field. You can find the working example at Golang Playground. I added a string representation to the Employee struct so that fmt.Println output is more redable.
In the case of having an extra nested key ({meta: {data: [...]}}), the types would be as follows:
type Employee struct {
ID int `json:"id"`
Name string `json:"name"`
Department string `json:"department"`
Designation string `json:"designation"`
}
type EmployeesData struct {
Data []Employee `json:"data"`
}
type Employees struct {
Meta EmployeesData `json:"meta"`
}
You can find the working example at Golang Playground too.
NOTE: I do not have context to name the structs properly, so I used Employees and EmployeesData but you should use more descriptive names that help understanding what the whole object represents and not only the meta and data fields.