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Re: Date calculating software?

  • To: mathgroup at
  • Subject: [mg30412] Re: Date calculating software?
  • From: Mark Westwood <mark at>
  • Date: Fri, 17 Aug 2001 03:09:51 -0400 (EDT)
  • References: <9ld133$2f3$>
  • Sender: owner-wri-mathgroup at


Mathematica can do simple things like add a number of days to a given 
date.  Have a closer look at the documentation for the 
Miscellaneous`Calendar standard add-on package, wherein you'll find a 
DaysPlus[date, numberOfDays] function.  You might want to check out the 
standard function Date[] first to check how Mathematica represents dates.

Adding a number of months is a little trickier - how long are the months 
you want to add ?  Are they solar-mean months, lunar months, does an 
added February have 28 or 29 days ?  If you're not too concerned with 
such niceties (or with the difficult question of how long a year is) 
then the standard add-on package Miscellaeous`Units has some predefined 
figures for Year, Month, Fortnight, etc.

And if you want to go a bit further into it 'Calendrical Calculations' 
by Dershowitz and Reingold give a good algorithmic treatment of a lot of 
the issues involved.

Happy computing
Mark Westwood
Pilot Solutions Ltd

Noz wrote:

> Hi
> Is there a software program or calculator available that can eg. Add a
> period of time to a date?
> example, today is 14 August 2001.
> 14082001 + 18 months
> or
> 14082001 + 1yr, 3mths, 4 days, and produces the date 1yr, 3mths and 4 days
> hence?
> Thanks in advance
> Noz
> --

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