计算文件中的行数 [英] Counting lines in a file

问题描述

计算StreamReader中的行数会更快：


（a）使用.ReadLine（）迭代文件并添加到counter，i ++


（b）执行.ReadToEnd（）然后使用IndexOf（）方法计算

出现的\\\ n $

（c）做一个.ReadToEnd（）并使用RegEx来计算出现次数

of \\\\ n >


-

Texeme Textcasting Technology
http://www.texeme.com

解决方案

嗨Javailo，

我猜这个选项c会更好地扩展，但是一个小测试可能会显示

真正的赢家;-)


Ward
ja*****@texeme.com 写道：

哪个会更快地计算StreamReader中的行数：

（a）迭代一个文件使用.ReadLine（）并添加到一个计数器，i ++
（b）做一个.ReadToEnd（），然后用一个IndexOf（）方法来计算\的出现\ （c）做一个.ReadToEnd（）并使用RegEx计算出现次数
of \\ n

我没有测试过，但是对于任意长度的文件可能都是A.


-

鲍勃鲍威尔[MVP]

Visual C＃，System.Drawing


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< ja ***** @ texeme.com>在消息中写道

新闻：Nf ******************** @ speakeasy.net ...

<在StreamReader中计算行数会更快：

（a）使用.ReadLine（）迭代文件并添加到计数器，i ++

（ b）执行.ReadToEnd（）然后使用IndexOf（）方法来计算\\\\ n的发生情况

（c）执行.ReadToEnd（）和使用RegEx计算
出现的数量



-
Texeme Textcasting Technology
http://www.texeme.com

我认为（b）应该是最快的，但我不希望任何重大的

之间的差异（ a）和（b）因为Windows在幕后进行高效的磁盘读取

缓冲。

我认为（c）应该是最慢的，因为RegExp。


无论如何，这只是猜测，为什么不尝试所有三种方法

并在此发布真实结果？ ;-)


-

此致，

Dmytro Lapshyn [Visual Developer - Visual C＃MVP]

< ja ***** @ texeme.com>在消息中写道

新闻：Nf ******************** @ speakeasy.net ...

<在StreamReader中计算行数会更快：

（a）使用.ReadLine（）迭代文件并添加到计数器，i ++

（ b）执行.ReadToEnd（）然后使用IndexOf（）方法来计算\\\\ n的发生情况

（c）执行.ReadToEnd（）和使用RegEx计算
出现的数量



-
Texeme Textcasting Technology
http://www.texeme.com

Which would be faster for counting lines in a StreamReader:

(a) iterate through a file using .ReadLine() and adding to a counter, i++

(b) doing a .ReadToEnd() and then using an IndexOf() method to count the
occurances of \r\n

(c) doing a .ReadToEnd() and using a RegEx to count the number of occurances
of \r\n


--
Texeme Textcasting Technology
http://www.texeme.com

解决方案

Hi Javailo,

I would guess that option c scales better, but a small test might show
the real winner ;-)

Ward

ja*****@texeme.com wrote:

Which would be faster for counting lines in a StreamReader:

(a) iterate through a file using .ReadLine() and adding to a counter, i++

(b) doing a .ReadToEnd() and then using an IndexOf() method to count the
occurances of \r\n

(c) doing a .ReadToEnd() and using a RegEx to count the number of occurances
of \r\n

I haven''t tested but probably A for any arbitrary length of file.

--
Bob Powell [MVP]
Visual C#, System.Drawing

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<ja*****@texeme.com> wrote in message
news:Nf********************@speakeasy.net...

Which would be faster for counting lines in a StreamReader:

(a) iterate through a file using .ReadLine() and adding to a counter, i++

(b) doing a .ReadToEnd() and then using an IndexOf() method to count the
occurances of \r\n

(c) doing a .ReadToEnd() and using a RegEx to count the number of
occurances
of \r\n


--
Texeme Textcasting Technology
http://www.texeme.com

Hi,

I think (b) should be the fastest, but I wouldn''t expect any significant
difference between (a) and (b) since Windows does efficient disk read
buffering behind the scenes.
I think (c) should be the slowest because of RegExp.

Anyway, it''s all just guessing, why don''t you try all the three approaches
and post the real result here? ;-)

--
Sincerely,
Dmytro Lapshyn [Visual Developer - Visual C# MVP]
<ja*****@texeme.com> wrote in message
news:Nf********************@speakeasy.net...

Which would be faster for counting lines in a StreamReader:

(a) iterate through a file using .ReadLine() and adding to a counter, i++

(b) doing a .ReadToEnd() and then using an IndexOf() method to count the
occurances of \r\n

(c) doing a .ReadToEnd() and using a RegEx to count the number of
occurances
of \r\n


--
Texeme Textcasting Technology
http://www.texeme.com

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