英文:
var organisations []Organisation creates an array of Organisation. But how may "container/list" create a list of Organisation (and not of anything?)
问题
第一种选择：使用切片
var organisations []*Organisation
for _, org := range ... { // 预计有2到10,000个项目
organisations = append(organisations, org)
}
- 我有强类型，
第二种选择：使用container/list
import "container/list"
organisations := list.New()
for _, org := range ... {
organisations.MoveToBack(org) // 被拒绝：无法将类型*Organisation用作类型*Element
}
- 它根本没有类型。如果我将这个列表发送给另一个函数，接收者将不会信任其内容，因为从其声明来看，它被填充了任何东西。
我该如何声明一个Organisation的列表？就像我可以创建一个它们的数组一样？
我的尝试被拒绝了，我不明白为什么。
英文:
First choice: using slice
var organisations []*Organisation
for _, org := range ... { // 2 to 10 000 items expected
organisations = append(organisations, org)
}
- I have strong typing,
Second choice: using container/list
import "container/list"
organisations := list.New()
for _, org := range ... {
organisations.MoveToBack(org) // Refused: cannot use type *Organisation as the type *Element
}
- it has no typing at all. If I send this list to another function, as it is, the receiver won't trust its content, as from its declaration it is filled with anything.
How may I declare a list of Organisation? Like I can create an array of them?
May attempt is refused, and I don't understand why.
答案1
得分: 2
你为什么认为使用切片会很慢？你有进行过测量吗？
切片插入，特别是如果你预先分配了切片的大小，是常数时间的：
organizations := make([]*Organization, 0, len(...))
在这之后，每次切片追加操作只是在数组中设置一个值。
即使你没有预先分配大小，切片也会根据需要进行动态调整和复制，但不是每个元素都会进行复制。
如果你使用列表，你会失去随机访问的能力，但你可以以常数时间高效地在列表的任意位置插入元素。
所以，根据你在构建之后的使用计划选择合适的解决方案。
英文:
Why do you think using slices would be slow? Have you measured?
Slice insertion, especially if you pre-allocate the slice, is constant-time:
organizations:=make([]*Organization,0,len(...))
After this, each slice-append is simply setting a value in an array.
Even if you do not pre-allocate it, the slice will be dynamically resized and copied as necessary, but not for each element.
If you use a list, you'll lose random access, but you can efficiently insert anywhere in the list in constant time.
So, pick the solution based on how you're planning to use it after construction.
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