// 已知list中元素"amber","jack"
arr := [...]string{"amber","jack"}
var set map[string]struct{}
set = make(map[string]struct{})
for _, value := range arr{
set[value] = struct{}{}
}
if _, ok := set["amber"];ok {
fmt.Println("amber is in the list")
} else {
fmt.Println("amber is not in the list")
}