数组与列表< T>:当要使用哪个?
MyClass[] array;
List<MyClass> list;
什么情况下,当一个是preferable比其他?为什么?
What are the scenarios when one is preferable over the other? And why?
这是罕见的,在现实中,你可能需要使用一个数组。绝对使用名单,其中,T&GT;
要添加/删除数据,因为调整阵列是昂贵的任何时候。如果您知道数据的长度是固定的,你要微优化某些非常特殊原因(基准之后),则阵列可能是有用的。
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.
名单,其中,T&GT;
提供的很多的不是一个数组更多的功能(尽管LINQ找齐了位),并且几乎总是正确的选择。除了 PARAMS当然
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
作为反 - 名单,其中,T&GT;
是一维的;在这里,你必须有矩形(等)阵列像 INT [,]
或字符串[,,]
- 但有一个对象模型建模这样的数据(如果需要)的其他方式。
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.
另请参阅:
- How/When放弃使用数组在C#.NET?
- 阵列,有什么意义呢?
- How/When to abandon the use of Arrays in c#.net?
- Arrays, What's the point?
不过,我利用阵列的一个很多在我的的protobuf -net 项目;完全是为了表现:
That said, I make a lot of use of arrays in my protobuf-net project; entirely for performance:
- 在它做了很多位移的,所以
字节[]
是pretty的编码多的基础; - 在我使用本地滚动
字节[]
缓冲区,我送下到底层流(和VV)前填写;比BufferedStream
快捷等; - 在内部使用对象的数组为基础的模式(
富[]
,而不是名单,其中,富&GT;
)中,由于大小是固定一旦建成,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 thanBufferedStream
etc; - it internally uses an array-based model of objects (
Foo[]
rather thanList<Foo>
), since the size is fixed once built, and needs to be very fast.
但是,这绝对是个例外;对于业务线的一般处理,一个名单,其中,T&GT;
胜每次
But this is definitely an exception; for general line-of-business processing, a List<T>
wins every time.