From: Ken Bloom <kbloom@...>
Date: 2008-10-28T06:40:27+09:00
Subject: Re: file manipulation

On Mon, 27 Oct 2008 13:35:28 -0700, Vandana wrote:

> Hi All,
> 
> I have one more question with file manipulation.
> 
> Suppose I have the following structure in a file : ---------------------
> Instance J1 (
> net n1()
> net n2 ()
> net n3()
> )
> Instance J2 (
> net n1()
> net n2()
> net n3()
> )
> Instance J3 (
> net n1()
> net n2()
> net n3()
> )
> -----------------------
> As an example, I want to read J3/net n3. (the files are huge ....in GB)
> I can grep for n3 but it will return 3 instances of n3.
> 
> How can I ensure that Im reading n3 values that belong to instance J3?
> 
> Thank you for your time. I really appreciate your help.
> 
> Thanks
> Vandana.

If your file was in XML, you could use REXML::Parsers::SAX2Parser (or 
some other SAX parser) to create a solution that turns on an 
@inInstanceJ3 variable when it encounters the right piece of data, turns 
off @inInstanceJ3 when it encounters the matching close tag, and records 
n3's only when @inInstanceJK3 is true.

For your format, I suggest you find a parser generator that lets you 
create actions for different grammar elements, to implement a similar 
solution.


-- 
Chanoch (Ken) Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu/~kbloom1/