golang判斷結構體為空

The size of an empty structure is zero in Golang. Here, empty structure means, there is no field in the structure.

在Golang中， 空結構的大小為零。 在此， 空結構表示該結構中沒有字段。

Eg:

例如：

    Type structure_name struct {
}

There are many ways to check if structure is empty. Examples are given below.

有很多方法可以檢查結構是否為空 。 示例如下。

Example 1:

范例1：

package main
import (
"fmt"
)
type Person struct {
}
func main() {
var st Person
if (Person{} == st) {
fmt.Println("It is an empty structure")
} else {
fmt.Println("It is not an empty structure")
}
}

It is an empty structure

Example 2:

范例2：

package main
import (
"fmt"
)
type Person struct {
age int
}
func main() {
var st Person
if (Person{20} == st) {
fmt.Println("It is an empty structure")
} else {
fmt.Println("It is not an empty structure")
}
}

It is not an empty structure

If a structure has fields, then how to check whether structure has been initialised or not?

如果結構具有字段，那么如何檢查結構是否已初始化？

Please follow given below examples...

請遵循以下示例...

Syntax:

句法：

    Type structure_name struct {
variable_name type
}

Example 1:

范例1：

package main
import (
"fmt"
"reflect"
)
type Person struct {
age int
}
func (x Person) IsStructureEmpty() bool {
return reflect.DeepEqual(x, Person{})
}
func main() {
x := Person{}
if x.IsStructureEmpty() {
fmt.Println("Structure is empty")
} else {
fmt.Println("Structure is not empty")
}
}

Output

輸出量

Structure is empty

Example 2:

范例2：

package main
import (
"fmt"
"reflect"
)
type Person struct {
age int
}
func (x Person) IsStructureEmpty() bool {
return reflect.DeepEqual(x, Person{})
}
func main() {
x := Person{}
x.age = 20
if x.IsStructureEmpty() {
fmt.Println("Structure is empty")
} else {
fmt.Println("Structure is not empty")
}
}

Output

輸出量

Structure is not empty

Using switch statement

使用switch語句

Example 1:

范例1：

package main
import (
"fmt"
)
type Person struct {
}
func main() {
x := Person{}
switch {
case x == Person{}:
fmt.Println("Structure is empty")
default:
fmt.Println("Structure is not empty")
}
}

Output

輸出量

Structure is empty

Example 2:

范例2：

package main
import (
"fmt"
)
type Person struct {
age int
}
func main() {
x := Person{}
switch {
case x == Person{1}:
fmt.Println("Structure is empty")
default:
fmt.Println("Structure is not empty")
}
}

Output

輸出量

Structure is not empty

翻譯自: https://www.includehelp.com/golang/how-to-check-if-structure-is-empty.aspx

golang判斷結構體為空