Following the Go by Example: JSON tutorial, I see how to work with a basic JSON string:
package main
import (
"encoding/json"
"fmt"
)
type Response struct {
Page int `json:"page"`
Fruits []string `json:"fruits"`
}
func main() {
str := `{"page": 1, "fruits": ["apple", "peach"]}`
res := Response{}
json.Unmarshal([]byte(str), &res)
fmt.Println(res.Page)
fmt.Println(res.Fruits)
}
// the output looks good here:
// 1
// [apple peach]
I would like to add some complexity to the str
data object that I am decoding.
Namely, I would like to add a key with a slice of maps as its value:
"activities": [{"name": "running"}, {"name", "swimming"}]
My script now looks like below example, however, for the life of me, I can not figure out what the correct syntax is in the Response
struct in order to get at the values in activities
. I know that this syntax isn't correct: Activities []string ...
but can not hack my way towards a solution that captures the data I want to display.
package main
import (
"encoding/json"
"fmt"
)
type Response struct {
Page int `json:"page"`
Fruits []string `json:"fruits"`
Activities []string `json:"activities"`
}
func main() {
str := `{"page": 1, "fruits": ["apple", "peach"], "activities": [{"name": "running"}, {"name", "swimming"}]}`
res := Response{}
json.Unmarshal([]byte(str), &res)
fmt.Println(res.Page)
fmt.Println(res.Fruits)
fmt.Println(res.Activities)
}
// the script basically craps out here and returns:
// 0
// []
// []
Thanks for any help!
Use []map[string]string:
type Response struct {
Page int `json:"page"`
Fruits []string `json:"fruits"`
Activities []map[string]string `json:"activities"`
}
Always check and handle errors. The example JSON has a syntax error which is corrected in the playground example.
I know this is an old one, but i've recently written utility for generating exact go type from json input and in similar case you could give it a spin: https://github.com/m-zajac/json2go
For this particular example it generates from json:
{"page": 1, "fruits": ["apple", "peach"], "activities": [{"name": "running"}, {"name": "swimming"}]}
go type:
type Object struct {
Activities []struct {
Name string `json:"name"`
} `json:"activities"`
Fruits []string `json:"fruits"`
Page int `json:"page"`
}