point := struct{ x, y int }{10, 20}
或是
point := new(Account)
更改值
point.x = 20
point.y = 30
傳值
package main
import "fmt"
type Point struct {
X, Y int
}
func main() {
point1 := Point{X: 10, Y: 20}
point2 := point1
point1.X = 20
fmt.Println(point2) // {20, 20}
}
傳地址
如果是傳遞指，則會更改到參照的物件
package main
import "fmt"
type Point struct {
X, Y int
}
func main() {
point1 := Point{X: 10, Y: 20}
point2 := &point1
point1.X = 20
fmt.Println(*point2) // {20, 20}
}
Struct inside Struct
type testS struct {
cc int
}
type ss struct {
testS
ccc int
}
func main() {
v := ss{testS: testS{cc: 22}, ccc: 1}
fmt.Println(v)
}
把func 加入到 struct內
有兩種方法：
第一種：
直接放入 struct
type ss struct {
ccc int
getApple func()
}
func main() {
v := ss{ccc: 1, getApple: func() {
fmt.Println(22)
}}
fmt.Println(v)
}
第二種：
之後寫 func ，然後將 struct 放在 func 名稱前
type Account struct {
id string
name string
balance float64
}
func (ac *Account) Deposit(amount float64) {
.....
}
account := &Account{"1234-5678", "Justin Lin", 1000}
account.Deposit(500)
例如原本要把參數傳進去才能呼叫 test ：
package main
import "fmt"
type connection struct {
message chan string
}
var conn = connection{
message: make(chan string),
}
func main() {
go test(conn.message)
msg := <-conn.message
fmt.Println(msg)
}
func test(messages chan string) {
messages <- "ping"
}
可以改為以下：讓test 變成 conn 的方法
package main
import "fmt"
type connection struct {
message chan string
}
var conn = connection{
message: make(chan string),
}
func (c *connection) test() {
c.message <- "ping"
}
func main() {
go conn.test()
msg := <-conn.message
fmt.Println(msg)
}
Value receiver, Pointer receiver
這邊要注意 connection 與 *connection 傳入時有分
Func 傳值與傳址
type MyStruct struct {
Val int
}
func myfunc() MyStruct {
return MyStruct{Val: 1}
}
func myfunc() *MyStruct {
return &MyStruct{}
}
func myfunc(s *MyStruct) {
s.Val = 1
}
The first returns a copy of the struct, the second a pointer to the struct value created within the function, the third expects an existing struct to be passed in and overrides the value.
iterate struct 內的值
package main
import (
"fmt"
"reflect"
)
type test struct {
a int
b int
}
func main() {
vb := test{a: 12, b: 13}
v := reflect.ValueOf(vb)
for idx := 0; idx < v.NumField(); idx++ {
keyNum := v.Field(idx)
fmt.Println(keyNum)
}
}
// 12
// 13
引入其他 package 的 struct
./user/schema.go
package user
type Schema struct {
ID int `json:"id"`
Name string `json:"name"`
Age string `json:"age"`
Account string `json:"account"`
Password string `json:"password"`
RegisterTime int64 `json:"registerTime"`
Gender string `json:"gender"`
City string `json:"city"`
}
main.go
import (
USER "./user"
)
func main() {
type User USER.Schema
....
}
