How to produce JSON with sorted keys in Go?

Question

In python you can produce JSON with keys in sorted order by doing

import json print json.dumps({'4': 5, '6': 7}, sort_keys=True, indent=4, separators=(',', ': ')) 

I have not found a similar option in Go. Any ideas how I can achieve similar behavior in go?

Answer 1

The json package always orders keys when marshalling. Specifically:

• Maps have their keys sorted lexicographically

• Structs keys are marshalled in the order defined in the struct

The implementation lives here ATM:

• http://golang.org/src/pkg/encoding/json/encode.go?#L359

Answer 2

Gustavo Niemeyer gave great answer, just a small handy snippet I use to validate and reorder/normalize []byte representation of json when required

func JsonRemarshal(bytes []byte) ([]byte, error) {     var ifce interface{}     err := json.Unmarshal(bytes, &ifce)     if err != nil {         return []byte{}, err     }     output, err := json.Marshal(ifce)     if err != nil {         return []byte{}, err     }     return output, nil }