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 ************ VITE, C'EST LE MOMENT DE VOUS ABONNER A L'ADSL !!! ********** Du 3 avril au 5 mai, s?rie limit?e ADSL 128K, cliquez vite ici : http://register.tiscali.fr/adsl/ Offre promotionnelle soumise ? conditions, r?serv?e aux nouveaux abonn?s ADSL Tiscali.