[R] getting package version inside .First.lib
Prof Brian Ripley
ripley at stats.ox.ac.uk
Thu Jan 27 09:07:13 CET 2005
On Thu, 27 Jan 2005, Adrian Baddeley wrote:
> Greetings -
>
> Is it possible, inside .First.lib,
> to find out the version number of the package that is being loaded?
>
> If only one version of the package has been installed,
> we could scan the DESCRIPTION file, something like
>
> .First.lib <- function(lib, pkg) {
> library.dynam("spatstat", pkg, lib)
> dfile <- system.file("DESCRIPTION", package="spatstat")
> ttt <- scan(dfile, what="", sep="^M", quiet=TRUE)[2]
"\n" not "^M", please, and readLines is better than scan here.
> vvv <- strsplit(ttt," ")[[1]][2]
> cat("spatstat version number",vvv,"\n")
> }
>
> but even this does not seem very safe (it makes assumptions about the
> format of the DESCRIPTION file).
It is better to use read.dcf or the installed description information in
package.rds. Take a look at how library() does this.
Post R-2.0.0 you can assume the format is as library uses.
BTW: all installed.packages does is to read the descriptions of all the
packages it finds, and in .First.lib you know the path to your package.
--
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
More information about the R-help
mailing list