结构体定义的一般方式如下:
type identifier struct { field1 type1 field2 type2 ... }
type T struct {a, b int}
也是合法的语法,它更适用于简单的结构体。
var t *T t = new(T)
变量 t
是一个指向 T
的指针,此时结构体字段的值是它们所属类型的零值,使用 new 函数给一个新的结构体变量分配内存,它返回指向已分配内存的指针。
无论变量是一个结构体类型还是一个结构体类型指针,都使用同样的 选择器符(selector-notation) 来引用结构体的字段,即:
type myStruct struct { i int } var v myStruct // v是结构体类型变量 var p *myStruct // p是指向一个结构体类型变量的指针 v.i p.i
struct实例:
package main import ( "fmt" "strings" ) type Person struct { firstName string lastName string } func upPerson(p *Person) { p.firstName = strings.ToUpper(p.firstName) p.lastName = strings.ToUpper(p.lastName) } func main() { // 1-struct as a value type: var pers1 Person pers1.firstName = "Chris" pers1.lastName = "Woodward" upPerson(&pers1) fmt.Printf("The name of the person is %s %s\n", pers1.firstName, pers1.lastName) // 2—struct as a pointer: pers2 := new(Person) pers2.firstName = "Chris" pers2.lastName = "Woodward" (*pers2).lastName = "Woodward" // 这是合法的 upPerson(pers2) fmt.Printf("The name of the person is %s %s\n", pers2.firstName, pers2.lastName) // 3—struct as a literal: pers3 := &Person{"Chris", "Woodward"} upPerson(pers3) fmt.Printf("The name of the person is %s %s\n", pers3.firstName, pers3.lastName) }
程序输出:
The name of the person is CHRIS WOODWARD The name of the person is CHRIS WOODWARD The name of the person is CHRIS WOODWARD
使用反射访问struct的tag标签:
package main import ( "fmt" "reflect" ) type Person struct { firstName string `An important answer` lastName string `The name of the thing` } func main() { tt := Person{"first", "last"} for i := 0; i < 2; i++ { refTag(tt, i) } }
程序输出:
Tag:An important answer Name:firstName Tag:The name of the thing Name:lastName
时间: 2024-09-29 16:49:03