Reflection to modify Go language data structure

The reflection package allows modification of Go data structures. The field values ​​of nested structures can be modified through reflection value (reflect.Value), structure field (reflect.StructField) and type (reflect.Type). The code gets the field index from the type information and uses the Elem() method to get the value of the embedded field, then modifies the value and updates the structure using the Set() method. When modifying nested structures, you need to pay attention to type compatibility and ensure that you have sufficient modification permissions.

Reflection modifies Go language data structure

Overview

Reflection of Go language Packages provide information for inspecting and manipulating runtime types and values. Through reflection, we can modify the contents of the data structure without rewriting the code.

Syntax

Reflection modification data structure mainly uses the following types:

• reflect.Value: represents the reflection value .
• reflect.StructField: Represents the reflection structure field.
• reflect.Type: Indicates the reflection type.

Practical case: modify nested structure

Consider the following nested structure:

type Inner struct {
    Value int
}

type Outer struct {
    Name string
    Inner
}

The following code is modified using reflectionOuter Structure’s Inner field:

package main

import (
    "fmt"
    "reflect"
)

func main() {
    // 创建并初始化 `Outer` 结构体
    o := Outer{Name: "Outer"}

    // 获取 `Outer` 的类型信息
    t := reflect.TypeOf(o)

    // 获取 `Inner` 的字段索引
    fieldIndex := t.FieldByName("Inner").Index

    // 设置 `Inner` 字段的值
    inner := o.Inner
    inner.Value = 42
    v := reflect.ValueOf(&o).Elem().FieldByIndex(fieldIndex).Elem()
    v.Set(reflect.ValueOf(inner))

    // 打印修改后的 `Outer` 结构体
    fmt.Println(o)
}

Output:

{Outer Inner{42}}

Notes

• When using reflection, you need to pay attention to type compatibility.
• For nested structures, you need to use the Elem() method to obtain the value of the embedded field.
• Ensure that you have sufficient permissions on the modified data structure.

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