[R] integers to POSIXct

[Prof Brian Ripley]

On Wed, 4 Oct 2006, paul sorenson wrote:

> What is the recommended way to convert/coerce and integer to a POSIXct
> please?
>
> d <- as.POSIXct(Sys.Date())
> i <- as.integer(d)
>
> as.POSIXct(i)
> Error in as.POSIXct.default(i) : do not know how to convert 'i' to class
> "POSIXlt"
>
> This appears to be the behaviour in 2.3.1 and 2.4.0 on windows XP.
>
> I have tried searching on this and found as.Date.integer in package zoo
> which performs a similar function but wondered if there was something
> basic I was missing in the base distribution?

It's documented on the help page for as.POSIXct in 2.4.0.  What that 
integer means is undefined unless you also tell R the time origin.

-- 
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