From xiao.gang.fan1 at libertysurf.fr  Sun Apr 27 19:14:28 2003
From: xiao.gang.fan1 at libertysurf.fr (=?iso-8859-1?Q?Fan?=)
Date: Sun Apr 27 18:14:41 2003
Subject: [Rd] Basic date time arithmetics operations
Message-ID: <HE0FS4$2E3B89086EAFD45D4CD3E4E7428A22AD@tiscali.fr>

Hello,

For basic date time arithmetics operations, AFAK, there're 
actually the function difftime() and the (dt + num) operations.

I'm wondering if other basic operations exist, like
add(dt, num, unit) where unit would be "y", "q", "m", etc. 

Also for the function seq.dates (or seq.POSIXt), the 
case for by="months" would be more useful if it takes
the situation of the end of month into account. 
For example,

> seq(ISOdate(2002,1,31), by="months", length=3)

"2002-01-31 13:00:00 CET" 
"2002-03-03 13:00:00 CET" 
"2002-03-31 13:00:00 CET"

rather than

"2002-01-31 13:00:00 CET" 
"2002-02-28 13:00:00 CET" 
"2002-03-31 13:00:00 CET"

Thanks
--
Fan

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[Rd] Basic date time arithmetics operations
=?iso-8859-1?Q?Fan?=