JSON Encoding without null values / dynamic struct creation

[Gyu-Ho Lee]

Hello,

I wonder what would be the best way to encode JSON with null values if I do not want to encode them in the JSON object. I am totally ok with many null values in encoded JSON. I just wonder if we can dynamically generate struct data type for each JSON object as we encode it, just for clearer output.

http://play.golang.org/p/fzeQnpdISo

type myData struct {

A string `json:"a_str"`

B string `json:"b_str"`

C string `json:"c_str"`

}

myMap := make(map[string][]myData)

data1 := myData{A: "hello", B: "gopher"}

data2 := myData{}

data3 := myData{A: "hey", B: "here", C: "golang"}

myMap["1"] = []myData{data1, data2, data3}

myMap["2"] = []myData{data2, data3}

myMap["3"] = []myData{data2}

buf := new(bytes.Buffer)

myMapInterface := make(map[string]interface{})

for k, v := range myMap {

myMapInterface[k] = interface{}(v)

}

err := json.NewEncoder(buf).Encode(myMapInterface)

if err != nil {

log.Fatal(err)

}

fmt.Println(buf.String())

// Is there anyway that I can exclude to encode empty elements in the struct?

// e.g. {"a_str":"","b_str":"A","c_str":""} -> {"b_str":"A"}

For example, when given {"a_str":"","b_str":"A","c_str":""}

is there anyway we can dynamically create a different struct like:

type _myData struct {

B string `json:"b_str"`

}

so that the encoded JSON does not have the null values in it

Thanks!

[Klaus Post]

Using omitempty?

http://play.golang.org/p/gJm-kiMHSg

/Klaus

[Gyu-Ho Lee]

This was exactly what I was looking for. Thanks!