UnmarshalJSON from []float64 to struct(Value)

test_json_unmarshal.go

// UnmarshalJSON from []float64 to struct(Value)
package main

import (
	"encoding/json"
	"fmt"
)

type Value struct {
	First  float64
	Second float64
	Last   float64
}

type Response struct {
	Values []Value
}

func (v *Value) UnmarshalJSON(b []byte) error {
	var numbers []float64
	err := json.Unmarshal(b, &numbers)
	if err != nil {
		fmt.Printf(err.Error())
		return err
	}
	v.First = numbers[0]
	v.Second = numbers[1]
	v.Last = numbers[2]

	return nil
}

func main() {
	data := []byte(`{"values": [[1, 2, 3], [4, 5, 6]]}`)

	res := new(Response)
	err := json.Unmarshal(data, &res)
	if err != nil {
		fmt.Printf(err.Error())
	} else {
		fmt.Printf("%f\n", res.Values[1].First)
	}
}