From: "baptiste Auguié" <ba208@...>
Date: 2007-06-29T20:48:41+09:00
Subject: newbie questions on processing numerical data from text files

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Hi,

Hope you can help me get started with these trivial questions.
I've got a practical problem, and the Ruby cookbook to help me, but a  
few combinations of the two haven't produced any interesting results  
yet. I'd need a simple useful example to start with and then make my  
own variations.

Here is my practical problem:

- I open a text file, locate a line according to some keyword or line  
number, and change a value
- I run a fortran program
- I read a text file (output of this program), extract several  
numerical values and export them in a two column text file

The way I've done that so far is using bash commands such as 'awk',  
'grep', ... but i need some loops and it's getting too big for a  
sensible bash script.

Could you help me get started in Ruby with the simpler example below?

Here is the content of "sampleTextFile.dat":

> this is a meaningless line
> another one
>
> maybe this line acts as a keyword for the following data
>
> 1 3.1 (415, 19e-12)
> 2 6 (3, 13e-14)
> 1 3.1 (415, 19e-12)
> 2 6 (3, 13e-14)
>
> other useless words ...


I would like to read this data in some sort of array/hash, and export  
the first column and the product of the last two columns to a new  
file "results.dat". This should be enough to understand the spirit I  
guess, with the probably trivial problem to call the external program.

Any advice welcome.

Many thanks in advance!

baptiste



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