Perl:给定年份和周数，我如何获得该周的第一个日期？

Question

使用优秀的 Perl DateTime模块获取日期的年份和星期数是微不足道的，但另一种方式似乎有点困难。如何获得以年份和周数开头的日期？

Answer 1

这是仅使用 DateTime 的一种方法:

use DateTime;

sub first_day_of_week
{
  my ($year, $week) = @_;

  # Week 1 is defined as the one containing January 4:
  DateTime
    ->new( year => $year, month => 1, day => 4 )
    ->add( weeks => ($week - 1) )
    ->truncate( to => 'week' );
} # end first_day_of_week


# Find first day of second week of 2012 (2012-01-09):
my $d = first_day_of_week(2012, 2);

print "$d\n";