Detailed explanation of the three laws of reflection in go language

Three Laws of Reflection: Type information byteization: Obtain type bytecode information, including field number and type. Value extraction reduction: Get the value object, then extract and set the field value. Type Alias ​​Reveal: Reveal the actual type of a type alias by getting its raw type.

Detailed explanation of the three laws of reflection in Go language

In Go language, reflection allows us to programmatically inspect and manipulate types and values. In order to make full use of reflection, we must understand its three basic laws:

1. Type information byteization law

import (
    "fmt"
    "reflect"
)

type MyStruct struct {
    Name string
    Age  int
}

func main() {
    // 创建一个 MyStruct 实例
    myStruct := MyStruct{Name: "John", Age: 25}

    // 获取其 Type 接口
    myType := reflect.TypeOf(myStruct)

    // 使用 NumField() 获取字段数
    numFields := myType.NumField()

    // 循环所有字段
    for i := 0; i < numFields; i++ {
        field := myType.Field(i)
        fmt.Printf("%s (%s)\n", field.Name, field.Type)
    }
}

Practical case: The above example shows how Use reflection to obtain field information in the structure. You can use this information to do things like dynamically create objects, serialize or deserialize them.

2. Value extraction and reduction law

import (
    "fmt"
    "reflect"
)

type MyStruct struct {
    Name string
    Age  int
}

func main() {
    // 创建一个 MyStruct 实例
    myStruct := MyStruct{Name: "John", Age: 25}

    // 获取其 Value 接口
    myValue := reflect.ValueOf(myStruct)

    // 根据字段索引获取字段值
    nameValue := myValue.FieldByName("Name")
    ageValue := myValue.FieldByName("Age")

    // 使用 Interface() 获取接口，然后断言为所需的值
    name := nameValue.Interface().(string)
    age := ageValue.Interface().(int)

    fmt.Printf("%s is %d years old.\n", name, age)
}

Practical case: The above example shows how to use reflection to extract the value of the field in the structure. You can use this feature to dynamically get and set properties of an object or create temporary objects with specific values.

3. The law of type alias revelation

import (
    "fmt"
    "reflect"
)

type AliasMyStruct = MyStruct

func main() {
    // 创建一个 AliasMyStruct 实例
    myStruct := AliasMyStruct{Name: "Jane", Age: 30}

    // 获取其背后的原始类型
    myType := reflect.TypeOf(myStruct)

    // 显示 Type 接口的类型
    fmt.Println(myType)

    // 获取其背后的真实类型
    underlyingType := myType.Elem()

    fmt.Println(underlyingType)
}

Practical case: The above example shows how to use reflection to reveal the actual type of a type alias. This is useful when dealing with type aliases and want to know the real type behind them.

The above is the detailed content of Detailed explanation of the three laws of reflection in go language. For more information, please follow other related articles on the PHP Chinese website!