golang：访问接口切片中的值

Question

I have a data structure which comes of out go-spew looking like this:

([]interface {}) (len=1 cap=1) {
 (string) (len=1938) "value"
}

It is of type []interface {}

How can I print this value with fmt, or access it in some way so that I can use it.

Answer 1

You can use type assertions or reflection work with the generic interface{} to an underlying type. How you do this depends on your particular use case. If you can expect the interface{} to be a []interface{} as in your example, you can:

if sl, ok := thing.([]interface{}); ok {
    for _, val := range sl {
        fmt.Println(val)
        // Or if needed, coerce val to its underlying type, e.g. strVal := val.(string)
    }
}

(Playground link)

If you can't make assumptions about the underlying type, you'll need to do some black magic using reflect.