# We assume $dt1 and $dt2 are during working hours, and
# we assume that DST changes will never occur during working hours, so
# we can ignore time zones.

use DateTime::Format::RFC3339 qw( );

my $format = DateTime::Format::Strptime->new(
   format    => '%Y-%m-%dT%H:%M:%S',
   time_zone => 'floating',
   on_error  => 'croak',
);

my $dt1 = $format->parse_datetime('2017-11-17T16:00:00');
my $dt2 = $format->parse_datetime('2017-11-22T17:10:00');

my $total = 0;

if (is_workday($dt1)) {
   ( my $eod = $dt1->clone() )
      ->set( hour => 17, minute => 30, second => 0, nanosecond => 0 );
   $total += $eod->delta_ms($dt1)->in_units('seconds')
      if $eod > $dt1;
}

if (is_workday($dt2)) {
   ( my $sod = $dt2->clone() )
      ->set( hour => 9, minute => 0, second => 0, nanosecond => 0 );
   $total += $sod->delta_ms($dt2)->in_units('seconds')
      if $sod < $dt2;
}

$dt1->truncate( to => 'day' );
$dt2->truncate( to => 'day' );
while (1) {
   $dt1->add( days => 1 );
   last if $dt1 >= $dt2;
   next if !is_workday($dt1);
   $total += 8.5 * 60;
}
[download]

Hello packetstormer,

An alternative solution to your problem could be to the use of Date::Manip module.

The module is very very powerful and with simple use of ""business" you can choose to only calculate the days that are business days and not holidays/weekends.

Business day for the module is considered 08:00am - 05:00pm (9 hours / 1 hour lunch). Sample of code below:

#!/usr/bin/perl
use strict;
use warnings;
use Date::Manip;

my $date_1 = "November 24 2017 4:59pm";
my $date_2 = "November 27 2017 08:01am";

my $sec = Delta_Format(DateCalc($date_1, $date_2, "business"), 0, "%st
+");
printf "diff secs: %d\n", $sec;

__END__

$ perl sample.pl
diff secs: 120
[download]

More information regarding the functions you can find here Date::Manip::DM5. If for any reason you want to change the hours/days you can do it through Date::Manip::Config/BUSINESS CONFIGURATION VARIABLES.

Update: Adding the Mode "business" explanation. The third parameter that you can add on the DateCalc function is $mode. This parameter when you do date calculations can take 6 different options. Sample from the documentation:

exact    : an exact, non-business calculation
semi     : a semi-exact, non-business calculation
approx   : an approximate, non-business calculation

business : an exact, business calculation
bsemi    : a semi-exact, business calculation
bapprox  : an approximate, business calculation
[download]

For more information you can read the official documentation Date::Manip::Calc/MODE.

Hope this helps, BR.

There are probably four main options from Date::Calc, Time::Piece, DateTime, and Date::Manip. Here's one of them off the top of my head for tomorrow (Friday) to next Wednesday at the times you suggested‐ Update: not working time here, so definitely not what you want though Mktime is a to_epoch routine.

perl -MDate::Calc=Mktime -E 'say abs Mktime(2017,11,24,16,33,0) - Mkti
+me(2017,11,29,17,10,0)'
434220
[download]

They want the number of working seconds.