From: Robert Klemme <shortcutter@...>
Date: 2010-07-23T03:07:55+09:00
Subject: Re: finding last line in a file

On 22.07.2010 16:22, Urabe Shyouhei wrote:
> (2010/07/22 22:06), Robert Klemme wrote:
>>> Then how about:
>>>
>>> File.open(f).each_line.inject(nil){|x,y|y}
>>>
>>> Slower than my first answer though.

>>   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.
>
> No, that can't work -- or that works only when you are sticking on the ASCII
> character set.  Multibyte encodings are not safe to read backwards
> (sometimes).  The only safe way is to read the whole content from the
> beginning, at least one time.

Good point.  Although pragmatically for fixed width and UTF-8 encoded 
files it will work and the performance gains for large files are 
significant enough to warrant this approach.

Cheers

	robert


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