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Re: the last line of a large file [message #55327 is a reply to message #55246]

Fri, 10 August 2007 10:39

James Kuyper
Messages: 425
Registered: March 2000

Senior Member

On Aug 10, 11:00 am, Carsten Lechte <c...@toppoint.de> wrote:
> Conor wrote:
>> lol! Really! What in the world is the point of putting the number of
>> lines at the end of the file?
>
> One legitimate reason would be that sometimes you only know how much
> data you have until after you have processed it all, especially if the
> data sets are so large that you only ever have a small subset in RAM.

That's easily worked around. Write a dummy length at the beginning of
the file, process data until you reach the end of the file, then go
back to the beginning of the file are overwrite the dummy length with
the correct one. For ASCII format files, that requires being very
careful to make sure that the dummy length is a sufficiently long
string, and that the final length is padded with spaces (or leading
0s) to have exactly the same size.

There are obvious limitations to this technique (i.e. the output has
to be seekable); but not seem applicable in this context.

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[Message index]

		the last line of a large file By: queiny on Thu, 09 August 2007 12:49
		Re: the last line of a large file By: David Fanning on Tue, 14 August 2007 10:42
		Re: the last line of a large file By: queiny on Tue, 14 August 2007 10:22
		Re: the last line of a large file By: little davey on Fri, 10 August 2007 14:15
		Re: the last line of a large file By: James Kuyper on Fri, 10 August 2007 10:39
		Re: the last line of a large file By: Conor on Fri, 10 August 2007 08:51

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