# phpman > perldoc > Date::Manip::Examples

## NAME
    [Date::Manip::Examples](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3AExamples/markdown) - examples of how to use [Date::Manip](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip/markdown)

## DESCRIPTION
    This document includes a number of examples on how to do common [Date::Manip](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip/markdown) operations. I will
    be happy to add new examples over time, and welcome suggestions and examples to include.

    In most cases, an example will include two different ways of getting the answer. The first way
    will be using the new (as of 6.00) OO modules. The second will be using the old-style functional
    interface.

    It should be noted that any time you want to work with alternate time zones, the OO interface is
    STRONGLY recommended since the functional interface does not preserve time zone information with
    the date, and may therefore give incorrect results in some cases. However, working in the time
    zone of the system should give correct results.

    It should be noted that, in the examples below, it appears that the OO method often requires
    more lines of code than the functional interface. There are a number of ways to shorten the OO
    method, but for the examples, I wanted to include all the steps explicitly.

## PARSING A DATE
    Dates can be parsed in practically any form in common usage:

    OO method
           $date = new [Date::Manip::Date](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ADate/markdown);
           $err = $date->parse("today");
           $err = $date->parse("1st Thursday in June 1992");
           $err = $date->parse("05/10/93");
           $err = $date->parse("12:30 Dec 12th 1880");
           $err = $date->parse("8:00pm December tenth");

    Functional
           $date = ParseDate("today");
           $date = ParseDate("1st Thursday in June 1992");
           $date = ParseDate("05/10/93");
           $date = ParseDate("12:30 Dec 12th 1880");
           $date = ParseDate("8:00pm December tenth");

    The [Date::Manip::Date](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ADate/markdown) manual has a list of all valid formats.

## PARSING AN AMOUNT OF TIME
    Amounts of time (referred to as deltas) can also be parsed:

    OO method
           $delta = new [Date::Manip::Delta](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ADelta/markdown);
           $err = $delta->parse("in 12 hours");
           $err = $delta->parse("-1:30:0");
           $err = $delta->parse("4 business days later");

    Functional
           $delta = ParseDateDelta("in 12 hours");
           $delta = ParseDateDelta("-1:30:0");
           $delta = ParseDateDelta("4 business days later");

## TO CALCULATE THE AMOUNT OF TIME BETWEEN TWO DATES
       $datestr1 = "Jan 30 1999 13:00 EST";
       $datestr2 = "2/Mar/1999 15:30:00 +0500";

    OO method
           $date1 = new [Date::Manip::Date](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ADate/markdown);
           $date2 = $date1->new_date();
           $err = $date1->parse($datestr1);
           $err = $date2->parse($datestr2);

        To get an exact amount of time between the two dates (expressed only in terms of hours,
        minutes, seconds), use:

           $delta = $date1->calc($date2);

        To get an approximate amount of time (expressed in terms of years, months, weeks, etc. in
        terms that a human would typically think of), use:

           $delta = $date1->calc($date2,"approx");

    Functional
           $date1 = ParseDate($string1);
           $date2 = ParseDate($string2);

        To get an exact amount:

           $delta = DateCalc($date1,$date2);

        and the approximate amount:

           $delta = DateCalc($date1,$date2,1);

    The [Date::Manip::Calc](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ACalc/markdown) manual has information about these, and other types of calculations.

## TO ADD AN AMOUNT OF TIME TO A DATE
    To find a second date a given amount of time before or after a first date, use the following:

       $datestr  = "Jan 30 1999 13:00 EST";
       $deltastr = "12 hours ago";
       $deltastr = "in 3 business days";

    OO method
           $date = new [Date::Manip::Date](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ADate/markdown);
           $delta = $date->new_delta();
           $date->parse($datestr);
           $delta->parse($deltastr);

           $d = $date->calc($delta);

    Functional
           $date = DateCalc($datestr,$deltastr);

    If the delta is a business delta, it will do a business mode calculation.

    The [Date::Manip::Calc](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ACalc/markdown) manual has information about these, and other types of calculations.

## COMPARE TWO DATES
    To take two different dates and see which is earlier, do the following:

       $datestr1 = "Jan 30 1999 13:00 EST";
       $datestr2 = "2/Mar/1999 15:30:00 +0500";

    OO method
           $date1 = new [Date::Manip::Date](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ADate/markdown);
           $date2 = $date1->new_date;
           $date1->parse($datestr1);
           $date2->parse($datestr2);

           $date1->cmp($date2);
              => -1, 0, 1

    Functional
           $date1 = ParseDate($datestr1);
           $date2 = ParseDate($datestr2);

           Date_Cmp($date1,$date2);
              => -1, 0, 1

## TO EXTRACT INFORMATION ABOUT A DATE OR DELTA
    If you have a date or a delta, you can extract information about them as follows:

       $datestr  = "1:24:08 PM EST Feb 3, 1996";
       $deltastr = "12 hours ago";

    OO method
           $date = new [Date::Manip::Date](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ADate/markdown);
           $delta = $date->new_delta();
           $date->parse($datestr);
           $delta->parse($deltastr);

           $str = $date->printf("It is now %T on %b %e, %Y.");
             =>  "It is now 13:24:08 on Feb  3, 1996."

           $str = $delta->printf("In %hv hours, %mv minutes, %sv seconds");
             => "In -12 hours, 0 minutes, 0 seconds";

    Functional
           $str = UnixDate($datestr,"It is now %T on %b %e, %Y.");
             =>  "It is now 13:24:08 on Feb  3, 1996."

           $str = Delta_Format($deltastr,"In %hv hours, %mv minutes, %sv seconds");
             => "In -12 hours, 0 minutes, 0 seconds";

    The [Date::Manip::Date](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ADate/markdown) manual contains all of the format codes that can be used to extract
    information from a date. The [Date::Manip::Delta](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ADelta/markdown) manual contains the codes for a delta.

## WORKING WITH EPOCH
    [Date::Manip](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip/markdown) can easily be used to work with the number of seconds since the epoch (Jan 1, 1970
    00:00:00 UTC).

    If you have a date, and you want to find out how many seconds it is after the epoch, you can do
    it in the following ways:

       $datestr  = "1999-04-30-15:30:00 EDT";
       $secs  = 1234567;

    OO method
        To find out how many seconds have elapsed on a certain date, you can do the following:

           $date     = new [Date::Manip::Date](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ADate/markdown);
           $err      = $date->parse($datestr);

           $str      = $date->printf('%s');
              => number of seconds

        To find out the date that is a certain number of seconds since the epoch, you can use the
        following:

           $date  = new [Date::Manip::Date](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ADate/markdown);
           $err   = $date->parse("epoch $secs");

        $date now contains the date wanted (in the local time zone)

    Functional
        To find out how many seconds have elapsed:

           $str = UnixDate($datestr,'%s');
             => number of seconds

        To find the date that is a number of seconds since the epoch:

           $date = ParseDateString("epoch $secs");

    Note that [Date::Manip](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip/markdown) will work with both positive seconds (for dates that have come since the
    epoch) and negative seconds (for dates that occurred before the epoch).

## RECURRING EVENTS
    To find a list of dates where a recurring event happens (even very complex recurrences), do the
    following:

    OO method
          # To find the 2nd Tuesday of every month from Jan 1 1999 to Apr 30 1999

          $recur = new [Date::Manip::Recur](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ARecur/markdown);
          $start = $recur->new_date();
          $end   = $recur->new_date();
          $start->parse("Jan 1 1999");
          $end->parse("Apr 30 1999");

          $recur->parse("0:1*2:2:0:0:0",$start,$end);
          @date = $recur->dates();

          # To find the Monday after Easter in 1997-1999

          $recur = new [Date::Manip::Recur](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ARecur/markdown);
          $recur->parse("*1997-1999:0:0:0:0:0:0*EASTER,ND1");
          @date = $recur->dates();

    Functional
          # To find the 2nd Tuesday of every month from Jan 1 1999 to Apr 30 1999
          @date = ParseRecur("0:1*2:2:0:0:0","","Jan 1 1999","Apr 30 1999");

          # To find the Monday after Easter in 1997-1999.
          @date = ParseRecur("*1997-1999:0:0:0:0:0:0*EASTER,ND1");

    The [Date::Manip::Recur](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ARecur/markdown) manual contains information about recurring events.

## WORKING WITH DATES IN ANOTHER LANGUAGE
    If you want to work with dates in a language other than English (but you are only working with a
    single language), do the following:

    OO method
           $date = new [Date::Manip::Date](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ADate/markdown);
           $date->config("Language","French","DateFormat","non-US");
           $date->parse("1er decembre 1990");

    Functional
           Date_Init("Language=French","DateFormat=non-US");
           $date = ParseDate("1er decembre 1990");

    The [Date::Manip::Config](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3AConfig/markdown) manual has a list of all supported languages (in the section on the
    Language config variable). The meaning of the DateFormat config variable is also included.

## WORKING WITH TWO DIFFERENT LANGUAGES
    If you want to work with dates in two (or more) languages, it is STRONGLY recommended that you
    use the OO interface. The functional interface will be much slower since it has to re-initialize
    a lot of language-specific stuff every time you switch back and forth between languages.

    OO method
           $date_eng = new [Date::Manip::Date](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ADate/markdown);
           $date_eng->config("Language","English","DateFormat","US");

           $date_fre = new [Date::Manip::Date](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3ADate/markdown);
           $date_fre->config("Language","French","DateFormat","non-US");

        Use the $date_eng object to do English operations, the $date_fre object to do French
        operations.

    Functional
        If you are working with both French and English dates, you can call the following to switch
        between them:

           Date_Init("Language=French","DateFormat=non-US");
           Date_Init("Language=English","DateFormat=US");

        This is NOT recommended. Use the OO method instead.

## BUGS AND QUESTIONS
    Please refer to the [Date::Manip::Problems](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip%3A%3AProblems/markdown) documentation for information on submitting bug
    reports or questions to the author.

## SEE ALSO
    [Date::Manip](https://www.chedong.com/phpMan.php/perldoc/Date%3A%3AManip/markdown) - main module documentation

## LICENSE
    This script is free software; you can redistribute it and/or modify it under the same terms as
    Perl itself.

## AUTHOR
    Sullivan Beck (<sbeck@cpan.org>)