How to Effectively Parse Complex JSON Structures in Go Using `json.Unmarshal`?

How to Parse a Complex JSON with Go Unmarshal: Unveiling the Inner Workings

The encoding/json package in Go offers the json.Unmarshal function to simplify JSON parsing tasks. However, encountering complex JSON structures can prove challenging.

Decoding into an Interface{}

For unknown JSON data, one can decode it into an interface{} using Unmarshal. This approach results in a map[string]interface{} value where keys are strings and values are interface{} types.

For instance, consider the following JSON:

{
     "k1" : "v1", 
     "k2" : "v2", 
     "k3" : 10, 
     "result" : [
                 [
                 ["v4", v5, {"k11" : "v11", "k22" : "v22"}]
                 , ... , 
                 ["v4", v5, {"k33" : "v33", "k44" : "v44"}
                 ]
                 ], 
                 "v3"
                ] 
}

The Go code to decode and access this data:

package main

import (
    "encoding/json"
    "fmt"
)

func main() {
    b := []byte(`{
       "k1" : "v1", 
       "k3" : 10,
       result:["v4",12.3,{"k11" : "v11", "k22" : "v22"}]
    }`)
    var f interface{}
    err := json.Unmarshal(b, &f)
    if err != nil {
        fmt.Println(err)
        return
    }
    m := f.(map[string]interface{})
    for k, v := range m {
        switch vv := v.(type) {
        case string:
            fmt.Println(k, "is string", vv)
        case int:
            fmt.Println(k, "is int", vv)
        case []interface{}:
            fmt.Println(k, "is an array:")
            for i, u := range vv {
                fmt.Println(i, u)
            }
        default:
            fmt.Println(k, "is of a type I don't know how to handle")
        }
    }
}

By asserting the interface type and utilizing a type switch, it's possible to navigat

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