Re^2: Date::Format handling of ISO week number format

> what's wrong with the following?
> :
> print time2str("%Y-W%W", time);

Because when the date falls in the first week of the year or the last week of the year, that'll be wrong about half the time. For instance,

use strict;
use warnings;

use Date::Manip qw<UnixDate>;
use Date::Parse qw<str2time>;
use Date::Format qw<time2str>;

print UnixDate("12/31/2007", "%L-W%W"), "\n";            # prints "200
+8-W01"
print time2str("%Y-W%W", str2time("12/31/2007")), "\n";  # prints "200
+7-W52" (!!)
[download]

Actually, I thought it would print "2007-W01" ... I guess D::F's %W is broken to go along with its lack of UnixDate-equivalent-%L. At least it works better than I thought, I suppose ... but of course, according to ISO 8601, 2007-W52 is still wrong.

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Re^3: Date::Format handling of ISO week number format by grinder (Bishop) on Jan 16, 2008 at 11:50 UTC
Ah, well that sucks. I would file a bug report. Since that doesn't work, I shall return to my first idea, which is to use Date::Calc. I didn't even know about Date::Format until you pointed it out. `#! /usr/local/bin/perl -w use strict; use Date::Calc 'Week_of_Year'; my ($y, $m, $d) = split m{/}, shift \|\| '2007/12/31'; my ($week,$year) = Week_of_Year($y, $m, $d); printf "%04d-W%02d\n", $year, $week;` [download] You might want to wrap that up in a little routine and be done with it. It will certainly be far faster than using Date::Manip • another intruder with the mooring in the heart of the Perl	[reply] [d/l]
Re^4: Date::Format handling of ISO week number format by Oberon (Monk) on Jan 16, 2008 at 23:48 UTC
That's a good idea, grinder. It won't be quite as easy as just writing a routine, since I have to be able to handle any given format coming in, but I think I can hack something together. Just scan the format for either %L or %W and, if I see either one, call Week_of_Year and do the substitution myself. Then I can pass it off to time2str if there are any %'s left. Not super elegant, perhaps, but definitely workable. Thanx!	[reply]