I have an array of generic type interface{}
and I would to check if that array contains a certain value in one of its JSON object.
history := reflect.ValueOf(historyInterface)
for i := 0; i < history.Len(); i++ {
// here I can get a map object
test := history.Index(i)
// then I tried to access the id property of the object
// but here it fails
fmt.Println("test", test["id"].(string))
}
Below is what test will look like for each iteration:
first iteration
map[id:5afbff19bf07c79c19ed9af9 date:Saturday, January 21, 2017 9:21 PM certitude:33]
second iteration
map[id:afbff198658487a3e3e376b date:Thursday, March 3, 2016 2:24 PM certitude:30]
invalid operation: test["id"] (type reflect.Valuedoes not support indexing)
If historyInterface
is created by unmarshaling JSON to an interface{}
, then the map has type map[string]interface{}
. Use a type assertion to get the map as that type:
history := reflect.ValueOf(historyInterface)
for i := 0; i < history.Len(); i++ {
test := history.Index(i).Interface().(map[string]interface{})
fmt.Println("test", test["id"].(string))
}
Also based on the assumption on the source of data, the application can use type assertions instead of reflect.
history := historyInterface.([]interface{})
for _, m := range history {
test := m.(map[string]interface{})
fmt.Println("test", test["id"].(string))
}