Does Date::Calc take this into account?

Yes:

use strict;
use warnings;

use Date::Calc qw ( Decode_Date_EU Week_of_Year );

my @date = ( 2006, 1, 1 );

print Week_of_Year( @date );

[download]

Prints 522005, ie the 52nd week of 2005.

In reply to Re^4: Getting Ordinal Number of a Week in a Given Date by Not_a_Number
in thread Getting Ordinal Number of a Week in a Given Date by Anonymous Monk

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