Extract value from an array in a Json-CodePudding

I'm trying to get "boots" value

My func main

varjson:=`{
  "identifier": "1",
  "name": "dumbname",
  "person": {
    "items": null,
    "inventory": [
      {
        "T-shirt": "black",
        "Backpack": {
          "BigPocket": {
            "spell": "healing",
            "boots": "speed",
            "shampoo": "Head & Shoulders"
          }
        }
      }
    ],
    "Pockets": null
  }
}`

var res map[string]interface{}

json.Unmarshal([]byte(varjson), &res)

test(res)

test function

    func test(t interface{}) {
      switch reflect.TypeOf(t).Kind() {
       case reflect.Slice:
        s := reflect.ValueOf(t)
    for i := 0; i < s.Len(); i   {
        fmt.Println(s.Index(i))
        }
      }
    }

But when I compile I get nothing If is there another way to get the "boot" value in the Json?

CodePudding user response：

Assuming you can use types, based on your comment (thankfully cause totally agree with colm, trying to reflect the structure is rough.

Once you have a type its super easy to navigate.

specifically fmt.Println(res.Person.Inventory[0].Backpack.BigPocket.Boots) would net you the boots value. Bearing in mind that Inventory is a slice so you probably need to iterate over that, whereas here I have directly accessed it, which will be bad if Inventory is empty or there are other elements.

package main

import (
    "encoding/json"
    "fmt"
)

type AutoGenerated struct {
    Identifier string `json:"identifier"`
    Name       string `json:"name"`
    Person     struct {
        Items     interface{} `json:"items"`
        Inventory []struct {
            TShirt   string `json:"T-shirt"`
            Backpack struct {
                BigPocket struct {
                    Spell   string `json:"spell"`
                    Boots   string `json:"boots"`
                    Shampoo string `json:"shampoo"`
                } `json:"BigPocket"`
            } `json:"Backpack"`
        } `json:"inventory"`
        Pockets interface{} `json:"Pockets"`
    } `json:"person"`
}

func main() {
    varjson := `{
  "identifier": "1",
  "name": "dumbname",
  "person": {
    "items": null,
    "inventory": [
      {
        "T-shirt": "black",
        "Backpack": {
          "BigPocket": {
            "spell": "healing",
            "boots": "speed",
            "shampoo": "Head & Shoulders"
          }
        }
      }
    ],
    "Pockets": null
  }
}`

    var res AutoGenerated
    json.Unmarshal([]byte(varjson), &res)
    
    fmt.Println(res.Person.Inventory[0].Backpack.BigPocket.Boots)
}

In your original, whats wrong is your switch statement only covers a slice, but the initial object is a map. So your switch is not finding a match initially