Programming Forums > Script Programming > Perl

tbohon · Oct 18th, 2006, 3:50 PM

This may be old news to some but at the same time may be of value to someone else.

I was recently faced with creating a date stamp for the previous day's date. Using some hints found online, I concocted the following routine which works nicely:

### function to build dstamp (date stamp for previous day's date)

my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time - 86400);

$mon = $mon + 1;
$year = $year + 1900;

$dstamp = sprintf "%04d%02d%02d", $year, $mon, $mday;

### end of dstamp function

The nice thing is that the value 86400 in the call to 'localtime' is equivalent to one (1) day ... so, by adjusting this value, you can create the same sort of date stamp (format is YYYYMMDD) for any offset.

Enjoy!

Tom

chrisranjana.com · Jan 15th, 2007, 10:22 AM

Will it take into account Daylight Savings time too ?

suppose yesterday was NON DST and today is a DST ?

Arevos · Jan 15th, 2007, 11:14 AM

Subtracting 86400 from the time will work most of the time, but not all of the time. If you need accuracy, use a module like DateTime:

 perl Syntax (Toggle Plain Text) 
use DateTime;
my $yesterday = DateTime->now->subtract( days => 1 );
use DateTime;
my $yesterday = DateTime->now->subtract( days => 1 );

Oct 18th, 2006, 3:50 PM	#1
tbohon Newbie Join Date: Mar 2006 Location: Olympia WA USA Posts: 11 Rep Power: 0	Date Routine This may be old news to some but at the same time may be of value to someone else. I was recently faced with creating a date stamp for the previous day's date. Using some hints found online, I concocted the following routine which works nicely: ### function to build dstamp (date stamp for previous day's date) my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time - 86400); $mon = $mon + 1; $year = $year + 1900; $dstamp = sprintf "%04d%02d%02d", $year, $mon, $mday; ### end of dstamp function The nice thing is that the value 86400 in the call to 'localtime' is equivalent to one (1) day ... so, by adjusting this value, you can create the same sort of date stamp (format is YYYYMMDD) for any offset. Enjoy! Tom __________________ My mind is like a steel whatchamacallit ...

Jan 15th, 2007, 10:22 AM	#2
chrisranjana.com Newbie Join Date: Jan 2007 Location: Chennai India Posts: 2 Rep Power: 0	Will it take into account Daylight Savings time too ? suppose yesterday was NON DST and today is a DST ? __________________ Chris, Director, Chrisranjana.com Web Developers and Software programmers

Jan 15th, 2007, 11:14 AM	#3
Arevos Programming Guru Join Date: Aug 2005 Location: England Posts: 1,499 Rep Power: 5	Subtracting 86400 from the time will work most of the time, but not all of the time. If you need accuracy, use a module like DateTime: perl Syntax (Toggle Plain Text) use DateTime; my $yesterday = DateTime->now->subtract( days => 1 ); use DateTime; my $yesterday = DateTime->now->subtract( days => 1 );

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Programming Forums > Script Programming > Perl

Date Routine