Message-ID: <Pine.LNX.4.61.0505122211400.32457@gannet.stats>
Date: 2005-05-12T21:15:18Z
From: Brian Ripley
Subject: Converting a number of minutes to a difftime
In-Reply-To: <4283BF42.7060909@metahuman.org>
On Thu, 12 May 2005, Martin C. Martin wrote:
> I have a variable "m" that contains the number of minutes that something
> lasted, e.g.
>
> m <- 139
>
> I'd like to convert it to a difftime, so I can add it to the POSIXct start
> time. But as.difftime seems to want a character string, with at most two
> characters for the minutes. All other conversion functions seem to take
> strings as well. What am I missing?
as.difftime() is quite limited. You need to get your hands dirty:
structure(m, units = "mins", class = "difftime")
will do the job.
Alternatively, Sys.time + (m*60) works.
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595