P
PerlFAQ Server
This is an excerpt from the latest version perlfaq4.pod, which
comes with the standard Perl distribution. These postings aim to
reduce the number of repeated questions as well as allow the community
to review and update the answers. The latest version of the complete
perlfaq is at http://faq.perl.org .
--------------------------------------------------------------------
4.16: How can I find the Julian Day?
(contributed by brian d foy and Dave Cross)
You can use the "Time:
iece" module, part of the Standard Library,
which can convert a date/time to a Julian Day:
$ perl -MTime:iece -le 'print localtime->julian_day'
2455607.7959375
Or the modified Julian Day:
$ perl -MTime:iece -le 'print localtime->mjd'
55607.2961226851
Or even the day of the year (which is what some people think of as a
Julian day):
$ perl -MTime:iece -le 'print localtime->yday'
45
You can also do the same things with the "DateTime" module:
$ perl -MDateTime -le'print DateTime->today->jd'
2453401.5
$ perl -MDateTime -le'print DateTime->today->mjd'
53401
$ perl -MDateTime -le'print DateTime->today->doy'
31
You can use the "Time::JulianDay" module available on CPAN. Ensure that
you really want to find a Julian day, though, as many people have
different ideas about Julian days (see
http://www.hermetic.ch/cal_stud/jdn.htm for instance):
$ perl -MTime::JulianDay -le 'print local_julian_day( time )'
55608
--------------------------------------------------------------------
The perlfaq-workers, a group of volunteers, maintain the perlfaq. They
are not necessarily experts in every domain where Perl might show up,
so please include as much information as possible and relevant in any
corrections. The perlfaq-workers also don't have access to every
operating system or platform, so please include relevant details for
corrections to examples that do not work on particular platforms.
Working code is greatly appreciated.
If you'd like to help maintain the perlfaq, see the details in
perlfaq.pod.
comes with the standard Perl distribution. These postings aim to
reduce the number of repeated questions as well as allow the community
to review and update the answers. The latest version of the complete
perlfaq is at http://faq.perl.org .
--------------------------------------------------------------------
4.16: How can I find the Julian Day?
(contributed by brian d foy and Dave Cross)
You can use the "Time:
iece" module, part of the Standard Library,which can convert a date/time to a Julian Day:
$ perl -MTime:
iece -le 'print localtime->julian_day'2455607.7959375
Or the modified Julian Day:
$ perl -MTime:
iece -le 'print localtime->mjd'55607.2961226851
Or even the day of the year (which is what some people think of as a
Julian day):
$ perl -MTime:
iece -le 'print localtime->yday'45
You can also do the same things with the "DateTime" module:
$ perl -MDateTime -le'print DateTime->today->jd'
2453401.5
$ perl -MDateTime -le'print DateTime->today->mjd'
53401
$ perl -MDateTime -le'print DateTime->today->doy'
31
You can use the "Time::JulianDay" module available on CPAN. Ensure that
you really want to find a Julian day, though, as many people have
different ideas about Julian days (see
http://www.hermetic.ch/cal_stud/jdn.htm for instance):
$ perl -MTime::JulianDay -le 'print local_julian_day( time )'
55608
--------------------------------------------------------------------
The perlfaq-workers, a group of volunteers, maintain the perlfaq. They
are not necessarily experts in every domain where Perl might show up,
so please include as much information as possible and relevant in any
corrections. The perlfaq-workers also don't have access to every
operating system or platform, so please include relevant details for
corrections to examples that do not work on particular platforms.
Working code is greatly appreciated.
If you'd like to help maintain the perlfaq, see the details in
perlfaq.pod.