Explain the use of Go's type assertion for accessing dynamic type information?

In Go, type assertions are used to extract a value of a specific type from an interface type. An interface type represents a set of methods, and can hold any value that implements those methods. However, when we want to access a value's underlying type, we need to use type assertion.

Type assertion is used to check if an interface value is of a certain type, and then extract the value of that type. The syntax for type assertion is:

value, ok := interfaceValue.(typeName)

Here, **interfaceValue** is the value of type **interface{}** that we want to extract the underlying value from, **typeName** is the name of the type we want to extract, **value** is the extracted value of type **typeName**, and **ok** is a boolean value that indicates whether the assertion was successful or not.

If the assertion is successful, the extracted value will be of type **typeName**. If the assertion fails, **value** will be set to the zero value of **typeName**, and **ok** will be **false**.

Type assertion is commonly used when working with interfaces and their implementations. For example, if we have an interface that represents a database connection, we can use type assertion to extract the underlying connection type and perform specific operations on it.

type DatabaseConnection interface {
    Connect() error
    Query(query string) ([]byte, error)
}

func QueryDatabase(conn DatabaseConnection, query string) ([]byte, error) {
    // Use type assertion to extract the underlying connection type
    dbConn, ok := conn.(*MyDatabaseConnection)
    if !ok {
        return nil, fmt.Errorf("invalid database connection type")
    }

    // Use the extracted connection type to perform the query
    return dbConn.Query(query)
}

In this example, we use type assertion to extract the underlying **MyDatabaseConnection** type from the **DatabaseConnection** interface, and then use that connection type to perform the query. If the assertion fails, we return an error indicating that the connection type is invalid.