From: Robert Klemme <shortcutter@...>
Date: 2010-07-22T22:06:35+09:00
Subject: Re: finding last line in a file

2010/7/22 Urabe Shyouhei <shyouhei@ruby-lang.org>:
> (2010/07/22 15:35), Robert Klemme wrote:
>> On 07/22/2010 07:10 AM, Urabe Shyouhei wrote:
>>> (2010/07/22 14:08), Urabe Shyouhei wrote:
>>>> Take a look at the doc for File.readline.
>>>
>>> Oops... typo.  I meant readlines.  With it you can do something like
>>> File.readlines(f).last
>>
>> This is as inefficient as using File.foreach because it will read the
>> whole file.  I believe Ted was looking for a more efficient solution.
>
> Then how about:
>
> File.open(f).each_line.inject(nil){|x,y|y}
>
> Slower than my first answer though.

This still reads in the whole file plus you do not close the File
object properly.  A solution that is efficient for large files will
use File#seek to move position to the end of the file and go backwards
from there.

Cheers

robert

-- 
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