It seems that you have load the "survival" package
date.mdy is a function from this one.
In this function the "origin" of the time is the first day of 1970
in the base package the origin is the first day of 1960
it's very curious...
Benjamin Esterni
France

From: "Vegard Andersen" <vegard.andersen@ism.uit.no>
Subject: [R] Date conversion problem using "as.Date"
To: "r-help@lists.r-project.org" <r-help@stat.math.ethz.ch>
Message-ID: <opsntv38wtk0a1dr@petter-smart>
Content-Type: text/plain; format=flowed; delsp=yes;
charset=iso-8859-15

Hello!

My problem is that the Julian date "behind" my dates seems to be wrong. I  
will examplify my problem.

t1 <- "1998-11-20"
t2 <- as.Date(t1)
# Here t2 is correctly "1998-11-20", but
date.mdy(t2)
$month
[1] 11
$day
[1] 19
$year
[1] 1988

And indeed, if I write: fix(t2) then I get : structure(10550, class =  
"Date"). So the Julian date is 10550, which is "1988-11-19", not the  
correct "1998-11-20"

If I instead of "as.Date" use "as.date", then things work ok. But I have  
not found out how to instruct "as.date" to handle dates from the 21st  
century.


I hope that someone can help me, thanks in advance!

-- 
Best regards,
Vegard Andersen
Institute of Community Medicine
University of Tromso
Tromso, Norway
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