清空已经赋值的struct

type A struct {
    Name string
    Level int
}

type B struct {
    Skill string
}

func main() {
    a := A{"Momo",1}
    b := B{"Starfall"}

    // outputs
    // {"Momo",1}
    // {"Starfall"}

    clear(a)
    clear(b)

    // outputs
    // {,0}
    // { }
}

func clear(v interface{}) {
    p := reflect.ValueOf(v).Elem()
    p.Set(reflect.Zero(p.Type()))
}

判断是否为空的strct

type Session struct {
    playerId string
    beehive string
    timestamp time.Time
}
session = Session{};

if (Session{}) == session  {
    fmt.Println("is zero value")
}
//或者判断其中一个值
if session.playerId == "" {
    fmt.Println("is zero value")
}

清空array和map

//清空array
var slice []string
slice = []string{"first"}
slice = slice[:0] //或者 slice = nil

//清空map
var m map[string]string
m = make(map[string]string)
m["name"] = "yourname"
m = nil
//或者这样
/*
for k := range m {
    delete(m,k)
}
*/