Golang : How to convert JSON string to map and slice



Tags : golang json-to-map json-to-slice array

Couple of simple examples on how to convert JSON string to map and slice(array).

Simple and straightforward way of converting one line of JSON string.


 package main

  import (
 "encoding/json"
 "fmt"
  )

  func main() {

 jsonStr := `{"Name":"Adam","Age":36,"Job":"CEO"}`

 personMap := make(map[string]interface{})

 err := json.Unmarshal([]byte(jsonStr), &personMap)

 if err != nil {
 panic(err)
 }

 for key, value := range personMap {
 fmt.Println("index : ", key, " value : ", value)
 }

  }

Output:

index : Name value : Adam

index : Age value : 36

index : Job value : CEO

Convert multiple lines of JSON string to map and append each line into a slice(array).


 package main

 import (
 "encoding/json"
 "fmt"
 "strconv"
 )

 func main() {

 jsonStr := `[{
 "Name": "Adam",
 "Age": 36,
 "Job": "CEO"
 }, {
 "Name": "Eve",
 "Age": 34,
 "Job": "CFO"
 }, {
 "Name": "Mike",
 "Age": 38,
 "Job": "COO"
 }]`

 type Person struct {
 Name string
 Age  int
 Job  string
 }
 var people []Person

 var personMap []map[string]interface{}

 err := json.Unmarshal([]byte(jsonStr), &personMap)

 if err != nil {
 panic(err)
 }

 for _, personData := range personMap {

 // convert map to array of Person struct
 var p Person
 p.Name = fmt.Sprintf("%s", personData["Name"])
 p.Age, _ = strconv.Atoi(fmt.Sprintf("%v", personData["Age"]))
 p.Job = fmt.Sprintf("%s", personData["Job"])
 people = append(people, p)

 }
 fmt.Println(people)

 } 

Output:

[{Adam 36 CEO} {Eve 34 CFO} {Mike 38 COO}]

References:

https://www.socketloop.com/tutorials/golang-iterate-map

https://www.socketloop.com/references/golang-encoding-json-decoder-decode-function-example

https://www.socketloop.com/tutorials/golang-covert-map-slice-array-to-json-xml-format

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  See also : Golang : Covert map/slice/array to JSON or XML format



Tags : golang json-to-map json-to-slice array

By Adam Ng

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