The reflect of "the.go.programming.language.2015.11"

This is a creation in Article, where the information may have evolved or changed.

• • Determine the type of reflectvalue and extract the data
  • Addressable
  • Gets the name of the struct method

Judge reflect. Value type and extract data

for reflect. Value type data, judged by kind ()

Func Formatatom (v reflect. Value) string {Switch V. Kind() {case reflect. Invalid: Return"Invalid"Case reflect. Int, reflect. IntReflect,. IntReflect,. Int8, reflect. Int64:return StrConv. Formatint(V. Int(),Ten) Case reflect. Bool: Return StrConv. Formatbool(V. Bool()) Case reflect. String: Return V. String() Default:return"No ex"}}

For other complex types of data

Func display (path string, v reflect. Value) {Switch V. Kind() {case reflect. Invalid: FMT. Println("") Case reflect. Slice, reflect. Array: For I: =0; i < V.len (); i++ {Display (FMT. Sprintf("%s[%d]", path, i), V. Index(i))} case reflect. Struct: For I: =0; i < V.numfield (); i++ {Fieldpath: = FMT. Sprintf("%s[%s]", Path, V. Type(). Field(i). Name) display (Fieldpath, V. Field(i))} case reflect. Map: For _, Key: = Range V. Mapkeys() {Display (FMT. Sprintf("[%s][%s]", Path, Formatatom (key)), V. Mapindex(key)) } default:fmt. Printf("%s=%s\n", Path, Formatatom (v))}}

Note that for structs using v.Type().Field(i).Name get domain names, take advantage of v.Field(i) getting domain values.

Addressable

Use CANADDR () members to determine whether addressable.
The following variables d are addressable and can be used d.Set(reflect.ValueOf(11)) to assign values.
You can also use d.Addr().Interface().(*int) the pointer to set the value, or you can take advantage of the d.SetInt(99) assignment:

func Addressable_main(){  x := 2 d: = reflect.  ValueOf (&x). Elem () FMT. Println (d.canaddr ()) D.Set (reflect.  ValueOf (one)) FMT. Println (x) DP: = d.Addr (). Interface (). (*int) *DP =  fmt. Println (x) D.setint (in) FMT. Println (x)   }

As follows: For variables of type int x , use rx.SetString("hello") causes panic. Variables of type interface{} can be used y or used ry.Set(reflect.ValueOf(3)) ry.Set(reflect.ValueOf("hello")) , but use can ry.SetInt(2) cause panic.

Func addressable_main2 () {x:=2Rx: = Reflect. ValueOf(&x). Elem() Rx. Setint(2) Rx. Set(Reflect. ValueOf(3))//Rx. SetString("Hello")//pannic varyinterface{} ry: = Reflect. ValueOf(&y). Elem() Ry. Set(Reflect. ValueOf(3)) Ry. Set(Reflect. ValueOf("Hello") FMT. Println(y)//Ry. Setint(2)//panic}func addressable_main3 () {stdout: = Reflect. ValueOf(OS. Stdout). Elem() FMT. Println(stdout. Type()) FD: = stdout. Fieldbyname("FD") FMT. Println(FD. Int())}

Gets the name of the struct method

The following code can see V as reflect. Variable of type value
Can be passed v.Method(i).Type().String() andv.Type().Method(i).Name()

func printmethodname (x  interface{}) {V: = reflect< Span class= "Hljs-preprocessor". ValueOf (x ) VT: = V () fmt ( "type%s \ n" , VT) for I: = 0   Methtype: = V (i)  () fmt (, VT, Vt (i) , Strings (Methtype (), )}}