Hello everyone,
I am graphing data with gnuplot and need to convert the incremental numbers I pull with my script to reflect the difference between the given day and the day before. So 02/03/2007 needs to subtract columns 3-6 with the same column numbers from 02/02/2007.
Here is how the data looks that I pulled:
02/02/2007 00:00:00 719267027 719244316 719233953 719240015
02/03/2007 00:00:00 720375777 720336674 720325633 720329849
02/04/2007 00:00:00 721640280 721640267 721522690 721552815
02/05/2007 00:00:00 722297206 722297203 722297203 722297206

And here is how im trying to get the data to look:
02/03/2007 00:00:00 1108750 1092358 1091680 1089834
02/04/2007 00:00:00 1264503 1303593 1197057 1222966
02/05/2007 00:00:00 656926 656936 774513 744391

As you can see im just subtracting one day against the other to pull the difference. Thats all I want but im not sure how to go about this with perl. I am able to do it in bash but its so ugly that I decided to attempt to learn how its done in perl. I would like to see how people will go about doing this and learn something from there expertise. This data is in a flat file and I am having trouble even getting off the ground on howto approach such a thing without using temp files.
Thanks in advance!

In reply to processing columns of text by sitnalta

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.