How to Read and Set Struct Fields with Reflection

Use the reflect package to get a reflect.Value of your struct, then call FieldByName to read or Set to write a field by its name.

import "reflect"

type Person struct {
    Name string
    Age  int
}

p := Person{Name: "Alice", Age: 30}
v := reflect.ValueOf(&p).Elem()

// Read
name := v.FieldByName("Name").String()

// Write
v.FieldByName("Age").SetInt(31)

Note: The struct must be passed as a pointer and the field must be exported (start with an uppercase letter) for Set to work.

Reflection lets your Go program inspect and modify its own data structures while it is running. It is like looking at a blueprint of a building to find a specific room, then changing what is inside that room without knowing the exact layout beforehand. You use this when building generic tools that need to handle many different types of data without writing specific code for each one.