[Python-Dev] datetime module enhancements (original) (raw)

Christian Heimes lists at cheimes.de
Fri Mar 9 17:03:16 CET 2007

Hello!

This is my first posting to the Python developer list so please forgive me if I'm doing something wrong.

In the past few weeks I've worked a lot with dates and times. I found several small annoyances in the datetime module. For example there was no obvious way to cast a timedelta to an int or float. I'm proposing some small additions to the datetime module:

td = timedelta(minutes=1, seconds=7, microseconds=500) int(td) 67 long(td) 67L float(td) 67.5 round(td) 68.0

datetime.datetime has a method (class factory) fromtimestamp() but its instances are missing a totimestamp() method that return the Unix timestamp for a date (seconds since 1970-01-01 00:00:00 UTC).

Some people might miss a from and to julian day number (JDN) and modified julian day (MJD) converter in datetime.date and datetime.datetime. MJD is used as base in VMS and JDN, MJD and RJD are used by astronomers. It's also very useful when one has to deal with dates before 0 and converting dates between foreign calendars.

From http://www.slac.stanford.edu/~rkj/crazytime.txt

November 17, 1858 is the base of the Modified Julian Day system.

The original Julian Day (JD) is used by astronomers and expressed in days since noon January 1, 4713 B.C. This measure of time was introduced by Joseph Scaliger in the 16th century. It is named in honor of his father, Julius Caesar Scaliger (note that this Julian Day is different from the Julian calendar named for the Roman Emperor Julius Caesar!).

http://en.wikipedia.org/wiki/Julian_Day

I'm willing to implement the features myself but I need a mentor who helps me to correct my code and applies it to the Python svn repository.

A patch for timedelta is already available at https://sourceforge.net/tracker/?func=detail&atid=355470&aid=1665292&group_id=5470

Comments?

Christian

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