Check out example codes for "type switch golang". It will help you in understanding the concepts better.

Code Example 1

var x interface{} = "foo"

switch v := x.(type) {
case nil:
    fmt.Println("x is nil")            // here v has type interface{}
case int: 
    fmt.Println("x is", v)             // here v has type int
case bool, string:
    fmt.Println("x is bool or string") // here v has type interface{}
default:
    fmt.Println("type unknown")        // here v has type interface{}
}

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