What is a Struct in Golang?

In Golang, a struct is like a custom data type that combines multiple different types of data fields into a meaningful whole. Structs are used to group related data toger.

Defining a Struct

Go requires you to explicitly define a struct using type keyword. You can't inline a struct definition. For example:，呵...

type Employee struct {
    User
    Salary float64
}

内卷。 This doesn't mean that Employee is a User; it just pulls up exported fields and methods of User so you can access m directly with e.Name and e.ID.

Accessing Struct Fields

You can access struct fields by using dot operator. For example, if you have a struct named Person with a field Address that contains fields City and State, you can access m like this:，我持保留意见...

var p Person
p.City = "New York"
p.State = "NY"

Instance Creation

Using new Function

The new function allocates memory for a value of type and returns a pointer to it. For example:

var e *Employee = new
e.User.Name = "John Doe"
e.Salary = 50000.00

Using var Keyword

You can also use var keyword to declare and initialize a struct. For example:，一言难尽。

var e Employee = Employee{
    User: User{Name: "Jane Doe"},
    Salary: 60000.00,
}

Using a Constructor Function

In Go, you can define constructor functions to initialize structs. For example:

func NewEmployee *Employee {
    return &Employee{
        User: User{Name: name},
        Salary: salary,
    }
}

Struct Embedding and Composition

Struct Embedding

Embedding is a way to include anor struct as a field in a struct. For example:，要我说...

type Dog struct {
    Animal
    Breed string
}

This allows you to access fiel 我舒服了。 ds of embedded struct directly.

Struct Composition

Composition is a way to create a new struct by combining fields from multiple structs. For example:，一针见血。

type Employee struct {
    User
    Salary float64
    Department *Department
}

Anonymous Fields and Method Sets

Anonymous Fields

划水。 You can define anonymous fields in a struct. For example:

type Employee struct {
    User
    *Department
}

Anonymous Method Sets

An anonymous method set is a set of methods defined by embe 打脸。 dding an interface or a type that has methods. For example:

type User interface {
    GetName string
    GetAge int
}
type Employee struct {
    User
}

Struct Tags

Struct tags are used to provide metad 什么鬼？ ata about struct fields. For example:

type Person struct {
    Name string `json:"name"`
    Age  int    `json:"age"`
}

Accessing Unexported Fields

The standard library reflect package defaults to disallowing read/write access to unexported fields. Attempting to do so will cause a panic:，地道。

reflect: : cannot return value obtained from unexported field or method

Conclusion

Structs in Golang are a powerful way to organize and structure your data. Understanding how to define and access struct fields, as well as how to use embedding and composition, can greatly enhance your ability to write efficient and readable code.

Written by: DummyWriter，稳了！

Date: 2025-09-25