Explain the use of Go's type assertions and type switches for handling and converting dynamic types in Go programs?

In Go, a type assertion is used to extract a value of a certain type from an interface type. It is used when you have an interface value and you want to access its underlying value of a specific type. A type assertion has the form x.(T), where x is the value of the interface type and T is the type that you want to extract. If x does not hold a value of type T, a runtime panic occurs. Here's an example:

var i interface{} = "hello"
s := i.(string)

In this example, **i** is an interface value that holds a string value. The type assertion **i.(string)** returns the string value and assigns it to the variable **s**.

A type switch, on the other hand, is used to compare the type of an interface value against a list of types and execute a block of code based on the matching type. A type switch has the form:

switch v := x.(type) {
case T1:
    // v has type T1
case T2:
    // v has type T2
    // no match; v has the same type as x

In this form of the switch statement, **x** is the interface value that you want to check, and **v** is the variable that will hold the value of the matching type. Each **case** represents a type that you want to check against, and the first matching case will execute its block of code.

Here's an example:

func doSomething(i interface{}) {
    switch v := i.(type) {
    case int:
        fmt.Printf("Twice %v is %v\n", v, v*2)
    case string:
        fmt.Printf("%q is %v bytes long\n", v, len(v))
        fmt.Printf("I don't know about type %T!\n", v)

func main() {

In this example, the **doSomething** function takes an interface value and uses a type switch to determine its type and execute a block of code accordingly. When called with an **int** value, it doubles the value and prints it. When called with a **string** value, it prints the length of the string. When called with a value of any other type, it prints an error message.

Related Questions You Might Be Interested