I'm trying to store a string into a slice field inside a struct. This is for collecting data and create a Json to post via to an API.
package main
type response1 struct {
Identifier string `json:"identifier"`
Family string `json:"family"`
Values struct {
Logo []struct {
Data string `json:"data"`
Scope string `json:"scope"`
} `json:"logo"`
}
}
func main() {
res2D := &response1{
Identifier: "1234567",
Family: "example",
}
res2D.Values.Logo[0].Data = "test"
res2B, _ := json.Marshal(res2D)
fmt.Println(string(res2B))
}
Error
And the error I got:
panic: runtime error: index out of range
goroutine 1 [running]:
main.main()
/tmp/sandbox507443306/main.go:22 +0xe0
You do not have to make the slice with appropriate size before hand. You can use append. What you are trying to do in your example is assign a slice "[0]" that has not been created yet, which is why you are getting your error. Use append and change your line
res2D.Values.Logo[0].Data = "test"
to
res2D.Values.Logo = append(res2D.Values.Logo,struct {Data string "json:\"data\"" }{Data: "test"})
and that will append the literal struct into your array. Now by looking at your code I am assuming you doing this as a test to explore the language so I wont go into detail on how to better write this without knowing what you are actually using it for.