Counting lines in a file

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jabailo

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
 
Hi Javailo,

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

Ward
 
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? ;-)
 
[email protected] said:
Which would be faster for counting lines in a StreamReader:
Click to expand...

The only way to find out is to test it, and in fact different ones may be faster depending on size and
characteristics of the file.
(a) iterate through a file using .ReadLine() and adding to a counter,
i++
Click to expand...

This is probably the best over all considering memory considerations etc if your file is large. And
probably the fastest too.
(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
Click to expand...

Both of these will consume large amoutns of memory if the file is large.


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hi,

the first option is the way to go, unless you are 100% sure that the size of
the file in advance.

The others solutions are not portable, you should use
Environment.NewLine() instead of "\r\n"

cheers,
 
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