What's the golang equivalent of converting any JSON to standard dict in Python?

Question

In Python you can do something like this:

r = requests.get(\"http://wikidata.org/w/api.php\", params=params)
data = r.json()

And now data

Answer 1

If you want a dictionary, use the Go type map[string]interface{} (which is a map with string keys and values of any type):

var data map[string]interface{}

And then you can refer to its elements like:

data["entities"]

See this example:

s := `{"text":"I'm a text.","number":1234,"floats":[1.1,2.2,3.3],
    "innermap":{"foo":1,"bar":2}}`

var data map[string]interface{}
err := json.Unmarshal([]byte(s), &data)
if err != nil {
    panic(err)
}

fmt.Println("text =", data["text"])
fmt.Println("number =", data["number"])
fmt.Println("floats =", data["floats"])
fmt.Println("innermap =", data["innermap"])

innermap, ok := data["innermap"].(map[string]interface{})
if !ok {
    panic("inner map is not a map!")
}
fmt.Println("innermap.foo =", innermap["foo"])
fmt.Println("innermap.bar =", innermap["bar"])

fmt.Println("The whole map:", data)

Output:

text = I'm a text.
number = 1234
floats = [1.1 2.2 3.3]
innermap = map[foo:1 bar:2]
innermap.foo = 1
innermap.bar = 2
The whole map: map[text:I'm a text. number:1234 floats:[1.1 2.2 3.3]
    innermap:map[foo:1 bar:2]]

Try it on the Go Playground.

Notes:

Basically if your map is multi-level (the map contains another map) like the "innermap" in the above example, when you access the inner map, you can use Type assertion to have it as another map:

innermap, ok := data["innermap"].(map[string]interface{})
// If ok, innermap is of type map[string]interface{}
// and you can refer to its elements.

Answer 2

I prefer to add a type declaration, that way you can add methods to simplify the type assertions:

package main

import (
   "encoding/json"
   "log"
   "net/http"
   "net/url"
)

type Map map[string]interface{}

func (m Map) M(s string) Map {
   return m[s].(map[string]interface{})
}

func (m Map) N(s string) float64 {
   return m[s].(float64)
}

func main() {
   v := url.Values{}
   v.Set("action", "wbgetentities")
   v.Set("format", "json")
   v.Set("ids", "Q24871")
   resp, e := http.Get("https://www.wikidata.org/w/api.php?" + v.Encode())
   if e != nil {
      log.Fatal(e)
   }
   data := Map{}
   json.NewDecoder(resp.Body).Decode(&data)
   pageid := data.M("entities").M("Q24871").N("pageid")
   println(pageid == 28268)
}

https://golang.org/ref/spec#Type_declarations