Re: [R] can I call user-created functions without source() ?

From: Duncan Murdoch <murdoch_at_stats.uwo.ca>
Date: Mon 19 Jun 2006 - 22:39:48 EST

Just a few comments below on alternative ways to do the same things:

On 6/19/2006 8:19 AM, Joerg van den Hoff wrote:

> for short term usage of some specialized functions I have added some
> lines to the `.Rprofile' in my home(!) directory as follows (probably
> there are smarter solutions, but at least it works):
>
> #source some temporary useful functions:
> fl <- dir(path='~/rfiles/current',patt='.*\\.R$',full.names=TRUE)
> for (i in fl) {cat(paste('source("',i,'")\n',sep="")); source(i)}
> rm(i,fl)

Another way to do this without worrying about overwriting some existing variables is

local({
fl <- ...
for (i in fl) ...
})

No need to remove fl and i at the end; they were created in a temporary environment, which was deleted at the end.

>
> here, I have put all the temporary stuff in a single dedicated dir
> `~/rfiles/current', but of course you can use several dirs in this way.
> all files in this dir with names ending in `.R' are sourced on startup
> of R. this roughly works like one of the directories on MATLAB's search
> path: every function definition in this directory is 'understood' by R
> (but everything is loaded into the workspace on startup, no matter,
> whether you really need it in the end: no real `load on demand').

It's possible to have load on demand in R, and this is used in packages.   It's probably not worth the trouble to use it unless you're using a package.

one
> important difference, though: this is only sensible for function
> definitions, not scripts ('executable programms' (which would directly
> be executed on R startup, otherwise).
> and, contrary to matlab/octave, this is not dynamic: everything is read
> in at startup, later modifications to the directories are not recognized
> without explicitely sourcing the files again.

There isn't really any reasonable way around this. I suppose some hook could be created to automatically read the file if the time stamp changes, but that's not really the R way of doing things: generally in R active things are in the workspace, not on disk. A good way to work is prepare things on disk, then when they are ready, explicitly import them into R.

>
> if you in addition you want to load definitions from the startup
> directory where you launch R (your project dir), the above could be
> modified to:
>
> #source some temporary useful functions from startup dir:
> fl <- dir(path=getwd(),patt='.*\\.R$',full.names=TRUE)
> for (i in fl) {cat(paste('source("',i,'")\n',sep="")); source(i)}
> rm(i,fl)
>
> in this way you at least don't need a separate `.Rprofile' in each
> project dir.

Another alternative if you want something special in the project is to create a .Rprofile file there, and put source("~/.Rprofile") into it, so both the local changes and the general ones get loaded.

Duncan Murdoch
>
>
>
> joerg
>
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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Mon Jun 19 22:44:22 2006

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