数组与列表<T>:何时使用哪个?

Array versus Listlt;Tgt;: When to use which?(数组与列表lt;Tgt;:何时使用哪个?)

问题描述

MyClass[] array;
List<MyClass> list;

在哪些情况下一种优于另一种?为什么?

What are the scenarios when one is preferable over the other? And why?

推荐答案

实际上，您很少会想要使用数组.任何时候你想添加/删除数据时，一定要使用 List<T>，因为调整数组大小很昂贵.如果您知道数据是固定长度的，并且您想出于某些非常具体的原因(在基准测试之后)进行微优化，那么数组可能会很有用.

It is rare, in reality, that you would want to use an array. Definitely use a List<T> any time you want to add/remove data, since resizing arrays is expensive. If you know the data is fixed length, and you want to micro-optimise for some very specific reason (after benchmarking), then an array may be useful.

List<T> 提供了比数组更多的功能很多(尽管 LINQ 稍微平衡了一点)，并且几乎总是正确的选择.当然，除了 params 参数.;-p

List<T> offers a lot more functionality than an array (although LINQ evens it up a bit), and is almost always the right choice. Except for params arguments, of course. ;-p

作为计数器 - List<T> 是一维的；where-因为您有矩形(等)数组，例如 int[,] 或 string[,,] - 但还有其他方法可以对此类数据进行建模(如果需要) 在对象模型中.

As a counter - List<T> is one-dimensional; where-as you have have rectangular (etc) arrays like int[,] or string[,,] - but there are other ways of modelling such data (if you need) in an object model.

另见:

• 如何/何时放弃使用c#.net 中的数组?
• 数组，有什么意义?

也就是说，我在 protobuf- 中大量使用了数组净项目；完全是为了性能:

That said, I make a lot of use of arrays in my protobuf-net project; entirely for performance:

• 它做了很多位移，所以 byte[] 对于编码来说非常重要；
• 我使用本地滚动 byte[] 缓冲区，在发送到底层流(和 v.v.)之前填充该缓冲区；比 BufferedStream 等更快；
• 它在内部使用基于数组的对象模型(Foo[] 而不是 List)，因为一旦构建，大小就固定了，并且需要非常快.

• it does a lot of bit-shifting, so a byte[] is pretty much essential for encoding;
• I use a local rolling byte[] buffer which I fill before sending down to the underlying stream (and v.v.); quicker than BufferedStream etc;
• it internally uses an array-based model of objects (Foo[] rather than List<Foo>), since the size is fixed once built, and needs to be very fast.

但这绝对是个例外；对于一般的业务线处理，List<T> 每次都会获胜.

But this is definitely an exception; for general line-of-business processing, a List<T> wins every time.

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