in reply to Re: where does the time go?
in thread where does the time go?

Sorry, DaWolf, that won't work.

If you're in March, on the 29th, 30th, or 31st, then the previous date you'd get your way won't work for Feb, 11 out of 12 times. (The 29th will work every 4 years, at least from now until 2100 :))

Obviously, you'll have the same problem every time a month with 31 days follows a month with 30, as well...

Date::Calc is clearly the way to go for this problem.
--
Mike

Replies are listed 'Best First'.
Re: The darned Feb problem :)
by Reverend Phil (Pilgrim) on Apr 24, 2002 at 19:05 UTC
    Ahh, while the deeper parts of this thread explain why that's a nasty thing to do for specific dates, in this particular application you should be fine. Our noble friend Anonymous Monk is just looking to roll the month back, so he can take those month values and work with them. Of course, he'll want to check to see if he's working with December and January, but otherwise, grabbing the month (and throwing a zero onto the front of a short one) should suffice. Working with the previous code (hacking stupidly, rather than grabbing a pretty module here), and handling both this and last month... 
    ($month, $year) = (localtime)[4..5];
# convert from index to 'normal'
$this_months_year = $year + 1900;
$last_months_year = $this_months_year;
$this_month = $month + 1;
# fix month if = 0
$last_month = $month;
$last_month or $last_month = 12;
# roll back year if this month is january
($this_month == 1) and $last_months_year--;
$this = sprintf("%04d%02d", $this_months_year, $this_month);
$last = sprintf("%04d%02d", $last_months_year, $last_month);

@files_this = <companyname.com-$this??_log>;
@files_last = <companyname.com-$last??_log>;

    [download]

    I think that looks a bit ugly, but that should at least illustrate why it's a good idea to peek into those date related modules. As a sidenote.. did I miss anything else in there, or should that ugly hack do the trick?

    -=rev=-
[reply]
[d/l]
      NICE ugly hack :)

      In fact, I used to have code very much like that.

      Then someone changed the interval from "1 month" to "20 days", and I started wishing I'd used Date::Calc right from the start...

      But your way should work fine for what he needs, as long as the specs don't change down the road.
      --
      Mike

[reply]
Re: The darned Feb problem :)
by DaWolf (Curate) on Apr 24, 2002 at 15:53 UTC
    Let me understand this.

    Shouldn't localtime return a value based on the OS date? So, how come it won't work?

    I need to clear this out.

    Er Galvão Abbott
     a.k.a. Lobo, DaWolf
    Webdeveloper
[reply]

      DaWolf,

      Imagine it's the 31st March. You subtract 1 from the month and get 31st February - which isn't a valid date.

      A similar problem occurs when it's any day in January. You subtract one from the month and get -1...

      Hope this helps!

[reply]
        Damn! You guys are right.

        I've never realized this. Sooo, time to rewrite some code... :)

        Er Galvão Abbott
         a.k.a. Lobo, DaWolf
        Webdeveloper
[reply]

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