How to iterate over an []interface{} in Go

Question

I'm struggling to get the keys and values of the following interface, which is the result of JSON marshaling the result returned by Execute as demonstrated in this example:

[
    [
        {
            "id": 36,
            "label": "TestThing",
            "properties": {
                "schema__testBoolean": [
                    {
                        "id": 40,
                        "value": true
                    }
                ],
                "schema__testInt": [
                    {
                        "id": 39,
                        "value": 1
                    }
                ],
                "schema__testNumber": [
                    {
                        "id": 38,
                        "value": 1.0879834
                    }
                ],
                "schema__testString": [
                    {
                        "id": 37,
                        "value": "foobar"
                    }
                ],
                "uuid": [
                    {
                        "id": 41,
                        "value": "7f14bf92-341f-408b-be00-5a0a430852ee"
                    }
                ]
            },
            "type": "vertex"
        }
    ]
]

A reflect.TypeOf(result) results in: []interface{}.

I've used this to loop over the array:

s := reflect.ValueOf(result)
for i := 0; i < s.Len(); i++ {
  singleVertex := s.Index(i).Elem() // What to do here?
}

But I'm getting stuck with errors like:

reflect.Value.Interface: cannot return value obtained from unexported field or method

Answer 1

If you know that's your data structure, there's no reason to use reflection at all. Just use a type assertion:

for key, value := range result.([]interface{})[0].([]interface{})[0].(map[string]interface{}) {
    // key == id, label, properties, etc
}