我该怎么用？ [英] What should I Use ?
问题描述
大家好，
想象一下我有一个int数组：
int [] anArray = new int [.. ];
我想提取所有优于500的整数
我能做到：
var result = new List< int>（）;
foreach（int in aArray）
if（i 500）
result.Add（i）;
或
var resultFind = Array.FindAll（anArray，elt = elt 500）;
或
var resultWhere = anArray.Where（elt = elt 500）;
或
var resultLinq =来自i in aArray，其中我500选择i;
最好的方法是什么？
感谢您的回答
Hi all,
Imagine I''ve an array of int :
int[] anArray = new int[..];
I want to extract all the integer that are superior to 500
I can do :
var result = new List<int>();
foreach (int i in anArray)
if (i 500)
result.Add(i);
or
var resultFind = Array.FindAll(anArray, elt =elt 500);
or
var resultWhere = anArray.Where(elt =elt 500);
or
var resultLinq = from i in anArray where i 500 select i;
What is the best way ?
Thanks for your answer
推荐答案
ti ********* @ gmail.com 写道：
想象一下我有一个int数组：
int [] anArray = new int [..];
我想要提取所有优于500的整数
我能做到：
var result = new List< int>（）;
foreach（int in anArray）
if（i 500）
result.Add（i）;
或
var resultFind = Array.FindAll（anArray，elt = elt 500）;
或
var resultWhere = anArray.Where（elt = elt 500）;
或
var resultLinq = from i在anArray中我选择i;
最好的方法是什么？
Imagine I''ve an array of int :
int[] anArray = new int[..];
I want to extract all the integer that are superior to 500
I can do :
var result = new List<int>();
foreach (int i in anArray)
if (i 500)
result.Add(i);
or
var resultFind = Array.FindAll(anArray, elt =elt 500);
or
var resultWhere = anArray.Where(elt =elt 500);
or
var resultLinq = from i in anArray where i 500 select i;
What is the best way ?
方法＃1和＃2创建新的收藏品，＃3和＃4没有（事实上他们确实没有创造任何东西;只有在评估时才会产生新的序列。
方法＃3和＃4使用LINQ（因此需要.NET 3.5），方法＃1和＃2做
$ b $不是。可读性是主观的，但＃1明显不如
其他三种方法。
因此答案是可预测的它取决于。一般来说，我会选择
在上下文中哪一方最方便（我需要一个List，一个
数组，一个IEnumerable吗？）并在转换时进行分析结果或其他
情况另有规定。孤立地说，这是一个太小的问题，
选择最佳方式。
-
J.
Methods #1 and #2 create new collections, #3 and #4 do not (in fact they do
not create anything; they will yield a new sequence only when evaluated).
Methods #3 and #4 use LINQ (and thus require .NET 3.5), methods #1 and #2 do
not. Readability is subjective, but #1 is obviously less direct than the
other three methods.
The answer is therefore predictably "it depends". In general, I''d pick
whichever one was most convenient in the context (do I need a List, an
Array, an IEnumerable?) and switch if profiling results or other
circumstances dictated otherwise. in isolation, it''s too small a problem to
pick the "best way".
--
J.
我的建议是写一个小的Windows窗体应用程序，它会产生一个大的数字，就像你要搜索的那个数字一样，然后在每一个后面添加4个按钮和
，把代码放到其中一个方法中。花时间执行
使用秒表进行搜索并查看每次拍摄需要多长时间。
秒表应该是一个高精度计时器，用于执行类似
的操作
这些。
尝试使阵列变大，因此技术之间的差异是暴露的。
发布结果，让我们知道。
-
Ciaran O''''Donnell
http://wannabedeveloper.spaces.live.com
" ti ****** ***@gmail.com"写道：
My suggestion would be to write a small windows forms app that makes a LARGE
array of number like the one you have to search, then add 4 buttons and
behind each one, put the code to do one of the methods. Time the execution of
the search using a stopwatch and see how long each takes.
The stopwatch is supposed to be a high accuracy timer for doing things like
these.
Try to make the array large so the difference between the techniques are
exposed.
Post the results and let us know.
--
Ciaran O''''Donnell
http://wannabedeveloper.spaces.live.com
"ti*********@gmail.com" wrote:
大家好，
想象一下我有一个int数组：
int [] anArray = new int [..];
我想提取所有优于500的整数
我能做到：
var result = new List< int>（）;
foreach（int in aArray）
if（i 500）
result.Add（i）;
或
var resultFind = Array.FindAll（anArray，elt = elt 500）;
或
var resultWhere = anArray.Where（elt = elt 500） ;
或
var resultLinq =来自i in aArray，其中我500选择i;
最好的方法是什么？
感谢您的回答
Hi all,
Imagine I''ve an array of int :
int[] anArray = new int[..];
I want to extract all the integer that are superior to 500
I can do :
var result = new List<int>();
foreach (int i in anArray)
if (i 500)
result.Add(i);
or
var resultFind = Array.FindAll(anArray, elt =elt 500);
or
var resultWhere = anArray.Where(elt =elt 500);
or
var resultLinq = from i in anArray where i 500 select i;
What is the best way ?
Thanks for your answer
Ciaran O''''Donnell< ; Ci ************ @ discussion.microsoft.comwrote：
Ciaran O''''Donnell <Ci************@discussions.microsoft.comwrote:
我的建议是w一个小的Windows窗体应用程序，使得你需要搜索一个大数字的数组，然后添加4个按钮和
后面的每一个，把代码放到做其中一种方法。花时间执行
使用秒表进行搜索并查看每次拍摄需要多长时间。
秒表应该是一个高精度计时器，用于执行类似
的操作
这些。
尝试使阵列变大，因此技术之间的差异是暴露的。
发布结果，让我们知道。
My suggestion would be to write a small windows forms app that makes a LARGE
array of number like the one you have to search, then add 4 buttons and
behind each one, put the code to do one of the methods. Time the execution of
the search using a stopwatch and see how long each takes.
The stopwatch is supposed to be a high accuracy timer for doing things like
these.
Try to make the array large so the difference between the techniques are
exposed.
Post the results and let us know.
请注意，这表示最佳 ==最快。我个人会选择
最可读的方法。对我来说，那是：
anArrayWhere（elt = elt 500）;
我只会开始担心性能我有一些证据表明
非常重要。
-
Jon Skeet - < sk *** @ pobox.com>
网站： http：// www。 pobox.com/~skeet
博客： http： //www.msmvps.com/jon_skeet
C＃深度： http ：//csharpindepth.com
Note that that suggests that "best" == "fastest". Personally I''d pick
the means which is the most readable. For me, that''s:
anArrayWhere(elt =elt 500);
I''d only start worrying about performance when I had some evidence that
it was really significant.
--
Jon Skeet - <sk***@pobox.com>
Web site: http://www.pobox.com/~skeet
Blog: http://www.msmvps.com/jon_skeet
C# in Depth: http://csharpindepth.com
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