How to Use Type Switches in Go

Use a type switch to execute different code blocks based on the dynamic type of an interface value by matching against specific types in the case clauses. The variable declared in the switch statement takes the type of the matched case within that block.

func describe(i interface{}) {
	switch v := i.(type) {
	case int:
		fmt.Printf("twice %v is %v\n", v, v*2)
	case string:
		fmt.Printf("%q is %d bytes long\n", v, len(v))
	default:
		fmt.Printf("unsupported type: %T\n", v)
	}
}

A type switch is a way to check what kind of data you are holding when the program doesn't know the exact type until it runs. It acts like a traffic cop that directs your code to the right path based on whether the data is a number, text, or something else. You use it whenever you need to handle different data types safely without causing your program to crash.