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Available environment variables

3 messages · Duncan Murdoch, Thompson, David (MNR)

Thompson, David (MNR)
# 
Hello,

I am trying to set my environment to streamline the downloading /
updating of packages. I have been through R-intro.html (10.8
Customizing-the-environment), R-FAQ (5.2 How can add-on packages be
installed?), rw-FAQ, and help pages for Sys.setenv {base},
download.packages {utils}, etc.,.

I am looking for something similar to the download.packages destdir
argument on a global environment level, e.g., destdir <- 'C:/Program
Files/_dave/stats/R/library/_download' in Rprofile.site. Any
suggestions?

Also, in a more general context, is there a way of listing all available
(or common, or default, or standard, . . .) environment variables? I
would like to know if there is an existing convention for any arbitrary
process that I may try to do without reinventing the wheel. This same
question could apply to options() other than those included with a
standard installation.

Thanks, DaveT.
*************************************
Silviculture Data Analyst
Ontario Forest Research Institute
Ontario Ministry of Natural Resources
david.john.thompson at ontario.ca
http://ofri.mnr.gov.on.ca
Duncan Murdoch
#
On 20/12/2007 2:13 PM, Thompson, David (MNR) wrote:
You could create your own function:

download.packages <- function(pkgs, destdir='C:/Program 
Files/_dave/stats/R/library/_download', ...)
   utils::download.packages(pkgs, destdir, ...)
Sys.getenv() will return a list of the ones that are currently defined.
  I
I don't know what you mean about an "arbitrary process".

For options(), you could save the names that you consider standard (e.g. 
by starting an empty session and entering standardoptions <- 
names(options()), then at a later time do

newoptions <- names(options())
newoptions[ !(newoptions %in% standardoptions) ]

There's no easy way to know the options that would mean something in the 
current context but are not currently defined.

Duncan Murdoch
Thompson, David (MNR)
# 
Thank you Duncan (additional comments below),
available
arbitrary
(e.g.
the
Creating a local copy of the function with alternate argument defaults
works perfectly. I have done that in the past, don't know why I didn't
think of it this time. Thank you.

Saving initial- and post-session options (or their names) also nicely
addresses part of my concern. Thank you.

I am familiar with Sys.getenv() and was asking about potential
environment variables that are NOT currently defined. However, while
trying to rephrase my question, having reread the Startup {base} help
and related documentation, could not clearly refine the issue in my own
mind so, I am now content with the situation.

I think that I may be confusing the intended use of environment files
and profile files as noted in the details section of the Startup {base}
documentation. Part of my concern is to find a way of safeguarding
against my own errors and typos that may 'break the system' or having
something installed later (the "arbitrary process" part) breaking my
current setup. Also, I may be thinking of the startup process as
something 'different' from the interactive R session processing, which I
am beginning to see it is not.

Thanks again, DaveT.
*************************************
Silviculture Data Analyst
Ontario Forest Research Institute
Ontario Ministry of Natural Resources
david.john.thompson at ontario.ca
http://ofri.mnr.gov.on.ca