R help - Mar 2011 - Storing user-defined R functions

Hello, I don't want to find out how to make packages unless that becomes
necessary. Also, I don't want to clog up the computer memory with functions
that I'm not using. (It would be great if someone in this forum would
explain how memory is used when I type library(MASS) and then use only one
function from MASS. Are all the many MASS functions then residing in memory,
or only the one I called?)

Is there some standard way of
1. storing the R functions that I define, each in a separate file in some
standard directory, and then
2. calling one of these functions without having to include the path to the
relevant directory?
3. If so, are there conventional places to keep such files, akin to
/usr/local/bin in Unix?

I'm thinking of a facility like Matlab's, when one has user-defined
paths
where Matlab will look for my Matlab functions. In my Matlab code, I don't
need to hard-wire in the path of the storage directory, and I can make the
function call as though my function is in the current directory.

Thanks,
David

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On Fri, Mar 25, 2011 at 5:11 AM, David.Epstein
<David.Epstein at warwick.ac.uk> wrote:
> Hello, I don't want to find out how to make packages unless that
becomes
> necessary. Also, I don't want to clog up the computer memory with
functions
> that I'm not using. (It would be great if someone in this forum would
> explain how memory is used when I type library(MASS) and then use only one
> function from MASS. Are all the many MASS functions then residing in
memory,
> or only the one I called?)
There is a lazy-loading system that loads functions and datasets only
on demand.  Not all packages use it, but MASS does.
> Is there some standard way of
> 1. storing the R functions that I define, each in a separate file in some
> standard directory, and then
> 2. calling one of these functions without having to include the path to the
> relevant directory?
> 3. If so, are there conventional places to keep such files, akin to
> /usr/local/bin in Unix?
No.

You really do want to learn to make packages.  It isn't that hard.

However, another possibility is to use save() to save a file
containing all your functions and then use attach() to make these
functions available.  This works like making a package except that you
don't get lazy-loading, you don't get documentation, and you don't
get
the package checks.

   -thomas

-- 
Thomas Lumley
Professor of Biostatistics
University of Auckland