How Can I Determine the Underlying Type of Go's `interface{}`?

Unveiling the True Nature of interface{}: Comprehensive Guide for Type Determination

When working with Go's versatile interface{} type, it's essential to navigate its inherent flexibility. To effectively utilize interface{}, we delve into your intriguing questions:

1. Unveiling the "Real" Type of w:

Type Switch to the Rescue:

switch v := w.(type) {
  case int:
    fmt.Println("Type: integer")
  case string:
    fmt.Println("Type: string")
}

2. Extracting the String Representation of a Type:

Utilizing TypeName:

fmt.Println(reflect.TypeOf(w).Name())

3. Converting a Value Using the String Representation of a Type:

Type Assertion with TypeName:

typeName := reflect.TypeOf(w).Name()
if typeName == "int" {
  value := w.(int)
} else if typeName == "string" {
  value := w.(string)
}

In your specific example, you can obtain the "real" type of w using a type switch:

switch w := weirdFunc(5).(type) {
  case int:
    fmt.Println("w is an integer")
  case string:
    fmt.Println("w is a string")
}

Alternatively, you can leverage the reflect package to retrieve the type name itself:

typeName := reflect.TypeOf(w).Name()
fmt.Println("w's type name:", typeName)

The above is the detailed content of How Can I Determine the Underlying Type of Go's `interface{}`?. For more information, please follow other related articles on the PHP Chinese website!