LPM: The times they are a-changin' (or: integer hash keys)

[Paul Stackhouse]

It appears to only be a problem on the exact day of the cross-over.  Once you
get to the ninth, when all of the entries are ten digits, everything sorts
properly again, right?  I'm still curious, though, about the answer to your
question.

	-paul

David Hempy wrote:
> 
> 
> Well, since Y2K was such a fizzle, we get another chance at notoriety on
> September 8, 2001, when we exceed 999,999,999 seconds since the
> epoch.  Shouldn't be a big deal, as that's only one less than 1,000,000,000
> seconds.
> 
> But yet, I'm facing it in one of my programs...
> 
> I got a call from a user complaining that September 8th's program schedule
> was out of order.  Everything after 9:30 PM (EDT) showed up first, before
> our first show at 8:00 AM.  Sure enough, she was right:
> 
> http://edit-www.ket.org/cgi-plex/schedule/ribbon_funnytime.pl?date=2001-09-08
> 
> It didn't take too long to figure notice the coincidence between the
> sorting problem and the 9+1 issue.  After convincing myself that SQL Server
> didn't know how to sort these values correctly (duh) I looked at my own code.
> 
> Turns out the problem was actually me not understanding how hash keys
> work.  I was using epoch times as hash keys.  It appears that hash keys are
> stored as strings, not the integers I was expecting.  For example:
> 
> $foo{1} = "one";
> $foo{2} = "two";
> $foo{3} = "three";
> $foo{10} = "ten";
> $foo{20} = "twenty";
> $foo{30} = "thirty";
> 
> foreach my $key (sort keys %foo) {
>         print "$key - $foo{$key}\n";
> }
> 
> 
> This produces this output:
> 1 - one
> 10 - ten
> 2 - two
> 20 - twenty
> 3 - three
> 30 - thirty
> 
> Any suggestions on a good way to sort hash keys by their integer values?
> 
> -dave
> 
> --
> David Hempy
> Internet Database Administrator
> Kentucky Educational Television - Distance Learning Division
> <hempy at ket.org> -- (859)258-7164 -- (800)333-9764

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