Go cannot exceed <my var> (type interface {})

Question

I am in the childhood stage, trying to plunge into the move. I am currently simulating an API request that returns a JSON string containing an array of objects. I am trying to find the most suitable way to iterate over each record and access each field. Ultimately, each field will be written to an Excel spreadsheet, but for now I just want to print each key and field value.

Here's what I have (I would provide it on the Go playground, but HTTP requests are not supported):

response, err := http.Get("http://go-proto.robwilkerson.org/demo.json") failOnError(err, "Uh oh") defer response.Body.Close() var view []interface{} json.NewDecoder(response.Body).Decode(&view) log.Printf(" [x] Pulled JSON: %s", view) for _, record := range view { log.Printf(" [===>] Record: %s", record) for key, val := range record { log.Printf(" [========>] %s = %s", key, val) } } 

Everything works fine until the nested loop tries to iterate over map , which contains the properties of each record:

 cannot range over record (type interface {}) 

I have two questions, I think:

• Is a nested loop the most efficient / effective way to access each property of each record?
• What do I need to do to get around this error?

UPDATE

When I upload data that is decoded into the view variable, this is the result of the registration:

 [ map[id:ef14912f-8031-42b3-8c50-7aa612287534 avatar:http://placehold.it/32x32 name:Vilma Hobbs email: [e-mail] phone:[phone] address:471 Dahill Road, Jacksonwald, Alabama, 6026] map[id:1b7bf182-2482-4b8b-8210-9dc9ee51069e avatar:http://placehold.it/32x32 name:Anne Dalton email: [e-mail] phone:[phone] address:660 Macdougal Street, Ticonderoga, Alaska, 7942] map[id:f8027852-f52e-4bbb-bc9d-fb5e34929b40 avatar:http://placehold.it/32x32 name:Amie Ray email: [e-mail] phone:[phone] address:878 Kane Street, Derwood, Minnesota, 3826] map[id:b9842ab7-5053-48b4-a991-f5c63af8fb7e avatar:http://placehold.it/32x32 name:Hope Benton email: [e-mail] phone:[phone] address:396 Osborn Street, Rowe, Massachusetts, 702] map[id:8f9f6d8d-d14e-4ddc-acb2-eb96d3c3d7a8 avatar:http://placehold.it/32x32 name:Janine Kidd email: [e-mail] phone:[phone] address:173 Manhattan Court, Hall, Virginia, 7376] map[avatar:http://placehold.it/32x32 name:Kristen Yang email: [e-mail] phone:[phone] address:203 Doughty Street, Westmoreland, Rhode Island, 849 id:210a6ae6-8227-4f26-a47c-448c400f26e9] map[name:Murray Sosa email: [e-mail] phone:[phone] address:811 Kingsland Avenue, Shepardsville, Hawaii, 9117 id:05f4f6af-19af-4b76-9aa8-9352281cf7d9 avatar:http://placehold.it/32x32] map[phone:[phone] address:176 Underhill Avenue, Ebro, Washington, 8099 id:9d21268d-067c-4b16-a6cd-42d184c4c059 avatar:http://placehold.it/32x32 name:Paige Stanton email: [e-mail] ] map[id:9946c19f-c226-4ff3-b578-57a249f8d0c7 avatar:http://placehold.it/32x32 name:Melisa Oconnor email: [e-mail] phone:[phone] address:768 Wallabout Street, Cotopaxi, Florida, 3388] map[id:ee0b82cb-4990-428b-ba36-088287a404ba avatar:http://placehold.it/32x32 name:Monique Poole email: [e-mail] phone:[phone] address:232 Hubbard Place, Islandia, Michigan, 3722] ] 

Answer 1

By default, which json packet will decode when the type is not declared:

 bool, for JSON booleans float64, for JSON numbers string, for JSON strings []interface{}, for JSON arrays map[string]interface{}, for JSON objects nil for JSON null 

Since each record is (in your example) a json object, you can claim each of them as map[string]interface{} like this:

 for _, record := range view { log.Printf(" [===>] Record: %s", record) if rec, ok := record.(map[string]interface{}); ok { for key, val := range rec { log.Printf(" [========>] %s = %s", key, val) } } else { fmt.Printf("record not a map[string]interface{}: %v\n", record) } }