Find week of a year given the date in mm/dd/yyyy

问题

I am trying to find the week that a date falls in, in a certain year. I have a bunch of files that need to be sorted into folders like "week1-2012" and "week34-2011". I tried searching but a lot of the results aren't really helping because I am currently using perl v5.6.1, super old and I can't download any modules. I also found this link ( How do I calculate the week number given a date?) of interest but was wondering how I would go about getting the day of year and week easily. Was thinking of getting the month, and adding the appropriate amount of days to find out the day in the year. Any help would be appreciated. An example of the year format I am looking for is

//year 2012
S  M  T  W  R  F  S
            1  2  3    <-- week #1 
4  5  6  7  8  9 10    <-- week #2 //came from the link

//dec year 2011
S   M  T  W  T  F  S
27 28 29 31            <-- week #52 or 53, not to sure the actual week

回答1:

You can use core modules: POSIX and Time::Local

1.parse your date to (sec, min, hour, mday, month, year)

2.convert your date to seconds (epoch)

3.use function strftime to get week from current date

use strict;
use Time::Local;
use POSIX qw(strftime);

my $date = '08/15/2012';
my ($month, $day, $year) = split '/', $date;

my $epoch = timelocal( 0, 0, 0, $day, $month - 1, $year - 1900 );
my $week  = strftime( "%U", localtime( $epoch ) );

printf "Date: %s № Week: %s\n", $date, $week;

OUTPUT

Date: 08/15/2012 № Week: 33

回答2:

Here's an alternate solution, using DateTime:

use strict;
use warnings;
use DateTime;

my $dt=DateTime->now(time_zone=>"local");
print $dt->week_number . "\n";

The output is, of course:

Edit: Of course you can download modules! If nothing else, you can copy and use the relevant code from DateTime.

回答3:

Perl 5.6.1 dates from April 2001. Someone is making your life much harder than it needs to be by not giving you modern tools to use. I suggest it's worth spending some time fixing that problem.

If you had Perl 5.10 or greater, then it would include the Time::Piece module. And your problem would become trivial.

#!/usr/bin/perl

use strict;
use warnings;
use 5.010;

use Time::Piece;

my $date = '08/15/2012';

my $dt = Time::Piece->strptime($date, '%m/%d/%Y');

say $dt->strftime('week%W-%Y');

Running it gives:

$ ./week 
week33-2012

This counts the week as Mon-Sun, not Sun-Sat.

来源：https://stackoverflow.com/questions/11974992/find-week-of-a-year-given-the-date-in-mm-dd-yyyy

标签

perl

date

time

dayofweek