Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hi,
I have to find the number of days remaining between 2 dates.

The dates are in the format

dd-mm-yyyy

into days

This is for an online auction so that I can tell people how many days are remaining until the item expires.

Many thanks,
Tom

Replies are listed 'Best First'.
Re: Converting dates
by gmax (Abbot) on Feb 04, 2003 at 23:44 UTC
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Re: Converting dates
by data64 (Chaplain) on Feb 04, 2003 at 23:46 UTC

    try Date::Calc module. Specifically the Delta_DHMS method.

    This is also answered in the Perl FAQ.

    Just a tongue-tied, twisted, earth-bound misfit. -- Pink Floyd

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Re: Converting dates
by bart (Canon) on Feb 05, 2003 at 00:21 UTC
    There's a standard module (as in "comes with perl"), Time::Local, which provides inverse functions for localtime and gmtime: timelocal() and timegm(). These can convert dates/times in a list format, (ss, mm, hh, dd, MM, yyyy), to an epoch time. As explained in How do I find the difference in days between two dates, in a cool perl way? which was pointed to in another reply, this is a number of seconds since, typically, January 1st 1970, 00:00:00 GMT. That is the case on Unix and Windows, at least.

    So first you must get your year/month/day out of the string: 

    $date = '05-02-2003';
my($d,$m,$y) = $date =~ /(\d+)-(\d+)-(\d+)/;

    [download]
    Subtract 1 from the month, as January is month 0. Seconds since the epoch can be found like this: 
    use Time::Local;
my $time = timegm(0, 0, 0, $d, $m-1, $y);

    [download]
    I use midnight, and GMT, as a reference, with regards to summer time issues — GMT doesn't have them. If you desire finer results, with an exact hours/minutes/seconds count, you can always use timelocal(), and real times.

    The calculated value is 1044403200. You can see that it works well, like this: 

    print scalar gmtime($time);

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    which produces 
    Wed Feb  5 00:00:00 2003

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     OK?
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Re: Converting dates
by tachyon (Chancellor) on Feb 05, 2003 at 01:21 UTC

    You may find these snippets useful 

    $d1 = '05-02-2003 10:30:44';
$d2 = '06-02-2003 11:31:47';

my ( $days, $hours, $mins, $secs ) = delta_date( $d1, $d2 );;
die "Auction expired" unless defined $secs;
print format_time_remaining( $days, $hours, $mins, $secs), 'remaining'
+;

sub delta_date {
    use Time::Local;
    my ($start, $end) = @_;
    my($d,$m,$y,$h,$min,$s) = split /[- :]/, $start;
    my $start_sec = timegm($s, $min, $h, $d, $m-1, $y);
    ($d,$m,$y,$h,$min,$s) = split /[- :]/, $end;
    my $end_sec = timegm($s, $min, $h, $d, $m-1, $y);
    my $diff = $end_sec - $start_sec;
  return undef if $diff < 0;
    my $days = int( $diff / (24*3600) );
    $diff -= $days * 24*3600;
    my $hours = int( $diff / (3600) );
    $diff -= $hours * 24*60;
    my $mins = int( $diff/ 60 );
    $diff -= $mins * 60;
  return $days, $hours, $mins, $diff;
}

sub format_time_remaining {
    ($days, $hours, $mins, $secs) = @_;
    my $str = '';
    $str .= $days  . ' day'    . (($days ==1 )  ? ', ' : 's, ');
    $str .= $hours . ' hour'   . (($hours == 1) ? ', ' : 's, ');
    $str .= $mins  . ' minute' . (($mins == 1)  ? ', ' : 's, ');
    $str .= $secs  . ' second' . (($secs == 1)  ? ' '  : 's ');
  return $str; 
}

    [download]

    cheers

    tachyon

    s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

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Re: Converting dates
by mojotoad (Monsignor) on Feb 05, 2003 at 06:27 UTC
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