英文:
append() to stuct that only has one slice field in golang
问题
我想将一个只包含单个匿名切片的结构体添加一个元素：
package main
type List []Element
type Element struct {
Id string
}
func (l *List) addElement(id string) {
e := &Element{
Id: id,
}
*l = append(*l, e)
}
func main() {
list := List{}
list.addElement("test")
}
这样做是行不通的，因为addElement将l视为指向List的指针，而不是切片：
go run plugin.go
# command-line-arguments
./plugin.go:13: first argument to append must be slice; have *List
最有可能起作用的方法是这样：
type List struct {
elements []Element
}
然后相应地修复addElement函数。除此之外，是否有更好的方法，例如让我保留type List的第一个定义？
非常感谢，sontags
英文:
I want to append an element to a struct that only consists of a single annonymous slice:
package main
type List []Element
type Element struct {
Id string
}
func (l *List) addElement(id string) {
e := &Element{
Id: id,
}
l = append(l, e)
}
func main() {
list := List{}
list.addElement("test")
}
That does not work, since addElement does not know l as slice but as *List:
go run plugin.go
# command-line-arguments
./plugin.go:13: first argument to append must be slice; have *List
What most likely would work is to go like this:
type List struct {
elements []Element
}
and fix the addElement func accordingly. I there a nicer way than that, eg. one that let me keep the first definition of type List?
Many thanks, sontags
答案1
得分: 8
两个问题，
-
你正在将
*Element追加到[]Element中，要么使用Element{}，要么将列表更改为[]*Element。 -
你需要在
addElement中取消引用切片。
示例：
func (l *List) addElement(id string) {
e := Element{
Id: id,
}
*l = append(*l, e)
}
英文:
Two problems,
-
You're appending
*Elementto[]Element, either useElement{}or change the list to[]*Element. -
You need to dereference the slice in
addElement.
func (l *List) addElement(id string) {
e := Element{
Id: id,
}
*l = append(*l, e)
}
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