Question

I had a problem with date manipulation.This is my scenario.I have a daily generating report files,they will be generated from Monday to Friday.Now I need to compare those reports.My perl code should work in such a way that if today is Monday I need to compare todays report with previous week Friday’s report.And my date format will be like this 20100803 if i give like this i need to be compared with 20100802. If i give Monday’s report i.e 20100802 it should compare with 20100730 i.e 30th of July. Can anyone please help me.

Thanks in Advance.

Answer 1

This won’t handle holidays (and you should really think about those), but it’s the minimal implementation in Perl:

use strict;
use warnings;

use POSIX ();

my $date_string = '20100802';
my ( $year, $month, $day ) = unpack 'A4 A2 A2', $date_string;
my $today = POSIX::mktime( 0, 0, 0, $day, $month - 1, $year - 1900 );
( $day, $month, $year, my $wday ) = ( localtime $today )[3..6];
my $day_back 
    = POSIX::mktime( 0, 0, 0, $day - ( $wday == 1 ? 3 : 1 ), $month, $year )
    ;
my $day_str = POSIX::strftime( '%Y%m%d', localtime( $day_back ));

Where $time is a specified time value.