List.empty vs. List()vs. new List() [英] List.empty vs. List() vs. new List()
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问题描述
List.empty
, List()
和之间的区别)
?
推荐答案
首先, new List()
将不工作,因为 List
类是抽象的。其他两个选项在 中定义如下,列表
对象:
First of all, new List()
won't work, since the List
class is abstract. The other two options are defined as follows in the List
object:
override def empty[A]: List[A] = Nil
override def apply[A](xs: A*): List[A] = xs.toList
也就是说,它们基本上是等同的,所以它主要是风格问题。我更喜欢使用 empty
,因为我发现它更清楚,并减少括号。
I.e., they're essentially equivalent, so it's mostly a matter of style. I prefer to use empty
because I find it clearer, and it cuts down on parentheses.
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