[R] ISOdate returns incorrect date?

Gabor Grothendieck ggrothendieck at myway.com
Wed Nov 19 17:06:29 CET 2003

ISOdate works, by default, in the GMT timezone. Try:


If you don't need timezones and don't want to worry about them
you can alternately use the chron library for your dates and 

Date: Wed, 19 Nov 2003 14:58:24 +0100 
From: Heiko Schaefer <heiko.schaefer at swissrisk.com>
To: <r-help at stat.math.ethz.ch> 
Subject: [R] ISOdate returns incorrect date? 


Dear all,

I have found the following (for me) incomprehensible behaviour of
ISOdate (POSIXct):
> ISOdate(1900,6,16)
[1] "1900-06-15 14:00:00 Westeuropäische Sommerzeit"
> ISOdate(1950,6,16)
[1] "1950-06-16 14:00:00 Westeuropäische Sommerzeit"

Note that in the first case I get the 15th of June back, not the 16th as
I would have expected!
This happened under R-1.7.1 on both windows and linux.

I would greatly appreciate your comments,


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