roho has asked for the wisdom of the Perl Monks concerning the following question:

I have super searched and googled to no avail, trying to find a module that converts a date in the form yyddd (or yyyyddd) to yyyymmdd (e.g, convert 11004 to 20110104). Does anyone know of a module that performs this conversion? I'm sure this wheel has already been invented somewhere. Thanks.

"Its not how hard you work, its how much you get done."

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Re: Date Conversion: yyddd to yyyymmdd
by GrandFather (Saint) on Jan 05, 2011 at 04:07 UTC

    There are plenty of date and time related modules, but in this case Date::EzDate may in fact be easy:

    my $date = Date::EzDate->new();

$date->{yeartwodigits} = 11;
$date->{yeardaybase1} = 32;
$date->{'myformat'} = '{year}{month number base 1}{day of month}';
print $date->{'myformat'};

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    Make sure you read the docs about the 'year two digits' handling of the assumed century however!

    True laziness is hard work
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Re: Date Conversion: yyddd to yyyymmdd
by Anonymous Monk on Jan 05, 2011 at 03:53 UTC
    Does anyone know of a module that performs this conversion? I'm sure this wheel has already been invented somewhere. Thanks.

    Pick pretty much any perl module, DateTime, Date::Manip, Time::Piece, and there are way to parse and format the date any way you want. The easiest way is with strftime/strptime

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Re: Date Conversion: yyddd to yyyymmdd
by ambrus (Abbot) on Jan 05, 2011 at 13:12 UTC

    The Date::Manip module accepts that format of dates by default (that is, it parses it fine without having to tell it the format), so let's use that. 

    $ perl -we 'use Date::Manip; print UnixDate($ARGV[0], "%Q\n")' 11004
20110104
$ perl -we 'use Date::Manip::Date 6.0; print Date::Manip::Date->new($A
+RGV[0])->printf("%Q\n")' 11004
20110104
$

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Re: Date Conversion: yyddd to yyyymmdd
by Ratazong (Monsignor) on Jan 05, 2011 at 08:48 UTC
    As other monks have shown above, there is more than one way to do it. I like Date::Calc (especially for its good documentation and examples!), so here is a way on how to do the conversion using that module: 
    
use Date::Calc qw(Add_Delta_Days);

my $input       = "11004";                            # yyddd
$input          =~ /(\d\d)(\d\d\d)/;
my ($y, $m, $d) = Add_Delta_Days("20$1",1,1, $2 -1);  # based on an ex
+ample in the Date::Calc-docu
my $output      = sprintf("%4d%02d%02d", $y, $m, $d);

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    HTH, Rata
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Re: Date Conversion: yyddd to yyyymmdd
by jwkrahn (Abbot) on Jan 05, 2011 at 07:44 UTC 
    $ perl -le'
use Time::Local qw/ timegm_nocheck /;

my $in_date = q/11004/;

my ( $in_year, $day_of_year ) = $in_date =~ /\A(\d\d|\d\d\d\d)(\d\d\d)
+\z/;

$in_year = ( ( 4 == length $in_year ? "" : "20" ) . $in_year ) - 1900;

my ( $day, $month, $year ) = ( gmtime timegm_nocheck 0, 0, 0, $day_of_
+year, 0, $in_year )[ 3, 4, 5 ];

printf "%d  %d  %d\n", $year + 1900, $month + 1, $day;
'
2011  1  4

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      Booo :) booo
      Read more... (2 kB)
      Doing your own century math is so 2001 1993 :) and oh look, Time::Piece->strptime seems to be broken
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        “I was dreamin’ when I wrote this, so sue me if I code too fast ...”

        – (with apologies to...) Prince; 1999.

Re: Date Conversion: yyddd to yyyymmdd
by Cristoforo (Curate) on Jan 05, 2011 at 16:37 UTC
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