From: dblack@...
Date: 2006-11-02T12:31:34+09:00
Subject: Re: Input file, change data, write to file

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Hi --

On Thu, 2 Nov 2006, Paul Br wrote:

> I'm a ruby newbie trying to read data from a file, make a few changes,
> and write the output to a file so it can be imported into a MySQL
> database.
>
> I found a partial solution on page 138 in Maik Schmidt's =E2=80=9CEnterpr=
ise
> Integration with Ruby=E2=80=9D book but it lacks a means to write the out=
put to
> a file.
>
> How can I write the output to a file using the below code?
>
> For what it's worth, I'll be working with files that contain between
> 20,000 =E2=80=93 60,000 rows.
>
> Below is a data sample:
>
> 01234567890123456789012345678901234567890123456789012
>
> 00123 random text   3.0010/20/200610/21/2006   -3.45
> 00253 more   text 275.0007/01/200606/12/2006   12.45
>
> Here's what I want the file to look like with tabs between each section:
>
> 01234567890123456789012345678901234567890123456789012
> 123 random text    3.00 2006-10-20 2006-10-21  -3.45
> 253 more   text  275.00 2006-07-01 2006-06-12  12.45

You might find scanf helpful.  Here's a little example.  Note that the
lines of data come from the DATA array, which is automatically read
from after __END__.  Also, I'm using values_at to manipulate the order
in which the values get inserted into the printf string, so that I can
put the years first.

   require 'scanf'
   DATA.each do |line|
     values =3D line.scanf("%5d %11c %4f %d/%d/%4d%d/%d/%d %f")
     printf("%3d%12s  %6.2f %04d-%02d-%02d %04d-%02d-%02d  %3.2f\n",
       *values.values_at(0,1,2,5,3,4,8,6,7,9))
   end

__END__
00123 random text   3.0010/20/200610/21/2006   -3.45
00253 more   text 275.0007/01/200606/12/2006   12.45


Output:

123 random text    3.00 2006-10-20 2006-10-21  -3.45
253 more   text  275.00 2006-07-01 2006-06-12  12.45


David

--=20
                   David A. Black | dblack@wobblini.net
Author of "Ruby for Rails"   [1] | Ruby/Rails training & consultancy [3]
DABlog (DAB's Weblog)        [2] | Co-director, Ruby Central, Inc.   [4]
[1] http://www.manning.com/black | [3] http://www.rubypowerandlight.com
[2] http://dablog.rubypal.com    | [4] http://www.rubycentral.org
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