Examples of basic tutorials for go language reflection

introduction

Reflection is a powerful and advanced concept in Go language. It allows us to introspectively look at variables at runtime, including the types, values, methods, etc. of the variables.

First, to use reflection, we need to importreflectBag:

import "reflect"

Type and value of reflection

In Go, each variable has a type and a value. For example, forvar x int = 3，xThe type isint, the value is3。

We can useandGet the type and value of a variable:

var x int = 3
((x))  // Output "int"((x)) // Output "3"

These two functions will returnandObjects of type, they contain the type and value information of the original variable.

Operation reflection value

Provides a series of methods to manipulate reflected values. For example, we can useInt()Method to obtain the integer value of the reflected value:

var x int = 3
v := (x)
(()) // Output "3"

Notice,Int()The method will produce panic when the type of the value is not an integer. If you are not sure about the type of value, you should use it firstKind()Method checks the type of value:

v := (x)
if () ==  {
    (()) // Output "3"}

Modify values by reflection

You can also modify the value through reflection, but it should be noted thatReturns a reflection value that is not modified. If you want to modify the original variable, you need to use(&x).Elem()Get the reflected value of the address of the variable, and then useSetIntMethod to modify it:

var x int = 3
v := (&amp;amp;x).Elem()
(4)
(x) // Output "4"

HereElem()The method returns the reflected value of the variable pointed to by the pointer, which is modifiable.

Summarize

Reflection is a very powerful feature in Go, which allows us to introspectively and modify variables at runtime. However, the use of reflection also requires caution, as the type safety of reflection operations is checked at runtime, not at compile time. This means that if you make mistakes while writing reflective code, panic may be generated at runtime.