look at the as.Date function
e.g.
as.Date("2007-04-21")- as.Date("2000-04-21")
also look at the chron library.
Regards
Wayne
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Daniel Brewer
Sent: 24 September 2007 11:23
To: [EMAIL PROTECTED]
Subject: [R] Calculate difference between dates in years
Hello,
I would like to be able to calculate the age of someone at a particular
date. Both dates are date objects. Here is what I have come up with:
floor(as.numeric(sampleInfo$Date.of.DIAGNOSIS-sampleInfo$Date.of.birth)/365.25)
Is this the best approach? or is there an inbuilt function? I have
looked at difftime but that does not seem to allow output in years.
Many thanks
Dan
--
**************************************************************
Daniel Brewer, Ph.D.
Institute of Cancer Research
Email: [EMAIL PROTECTED]
**************************************************************
The Institute of Cancer Research: Royal Cancer Hospital, a charitable Company
Limited by Guarantee, Registered in England under Company No. 534147 with its
Registered Office at 123 Old Brompton Road, London SW7 3RP.
This e-mail message is confidential and for use by the =\ ad...{{dropped}}
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
