[R] "attach" in R corr. to Spus one

[Liaw, Andy]

Hi Petr,

I don't think I've said anything that is inconsistent with what you said,
have I?

The strategy that you mentioned is the one that is recommended, and I use it
myself.  However, life is not always that simple.  There are times when the
task at hand involves data/code/whatever that live in a different directory
(perhaps most likely either the parent- or sub-directory of pwd).

.RData is just a .rda file, and thus can be attach()ed, and that's what I
said in my sentence.  E.g., I can attach("subdirectory/.RData"), then use
ls(2) to see what's in there.  (ls() does have a few optional arguments.)
Regarding save(), you can save to anywhere by using full path in the file
name (otherwise it wouldn't be terribly useful).

Best,
Andy

> From: Petr Pikal
> 
> Hallo Andy,
> 
> Well, my original respond was to Utsav's question if it is 
> possible to attach a 
> directory in R as in S+.
> 
> I personally prefer to start R session from a directory where 
> I have all data and 
> results from certain project (txt, doc, xls, png, pdf....). 
> Therefore I use only 
> .RData and I usually store histories of my work in separate 
> files, so as basically all 
> my data and my knowledge of attaching different directories 
> in one session is not 
> at all comprehensive. 
> 
> But if I am not mistaken you cannot attach a directory 
> without some suitable file 
> (.RData or saved file) in it but you can specify different 
> working directory by 
> setwd() and list files in it by list.files(). I presume that 
> after setwd() I can 
> attach(".RData") to get access to objects from it but ls() 
> still gives me list of 
> objects stored in an .RData file in the directory from which 
> R was started.
> 
> OTOH saving an object by save(object, file="myfile") saves 
> the object to 
> directory specified by setwd().
> 
> Cheers
> Petr
> 
> On 9 Jun 2004 at 9:00, Liaw, Andy wrote:
> 
> > Now that I acutally read the original question:
> > 
> > If there are .RData files in other directories that you want to
> > attach(), you can certainly do that.  One difference between R and
> > S-plus is that in S-plus you can attach() a directory at position 1,
> > effectively making that the place that new objects are 
> stored.  In R,
> > attach()ing at position 1 is not allowed.  I must say that 
> I like the
> > way R works better, as it does a better job at preventing me from
> > keeping garbage around.
> > 
> > Best,
> > Andy
> > 
> > > From: Liaw, Andy
> > > 
> > > > From: Frank E Harrell Jr
> > > > 
> > > > Petr Pikal wrote:
> > > > > Hallo
> > > > > 
> > > > > On 9 Jun 2004 at 2:06, Utsav Boobna wrote:
> > > > > 
> > > > > 
> > > > >>Hi,
> > > > >>    I am a newbie to R, just trying to switch from
> > > > >>Splus. I am wondering to know if there is any such
> > > > >>command in R as "attach" in Splus which can be used to
> > > > >>attach the full directory.
> > > > > 
> > > > > 
> > > > > I would recommend you to spent some time going through 
> > > > docummentation and 
> > > > > especially FAQs. 
> > > > > 
> > > > > getwd and setwd for setting the working directory
> > > > > 
> > > > > but in R objects are stored in one file .Rdata.
> > > > 
> > > > I prefer to control which objects are stored, and to use 
> > > > compression, by 
> > > > using save( ) and load( ), rather than using the .Rdata 
> mechanism.
> > > > save( ) can store one object or an entire series of 
> objects in one
> > > > .rda file.
> > > 
> > > I mostly do the same.  For fairly large objects or objects 
> > > that I do not
> > > want to accidentally alter during a session, I use 
> attach() instead
> > > of load().  One convenience of attach() is that since the objects
> > > are not loaded into .GlobalEnv, I would have a less 
> cluttered .RData
> > > even if I do save the workspace when I q().
> > > 
> > > Cheers,
> > > Andy
> > > 
> > >  
> > > > Frank
> > > > 
> > > > > 
> > > > > OTOH in S+ objects are (were - I did not use it since quite 
> > > > a lot time) stored as 
> > > > > separate files.
> > > > > 
> > > > > For attaching objects see
> > > > > 
> > > > > ?attach
> > > > > 
> > > > > Cheers
> > > > > Petr
> > > > > 
> > > > > 
> > > > >>Also, any idea/referrence about, how to load c
> > > > >>functions in R would be highly appreciated.
> > > > >>
> > > > >>Thanks,
> > > > >>Utsav
> > > > > 
> > > > > Petr Pikal
> > > > > petr.pikal at precheza.cz
> > > > > 
> > > > > ______________________________________________
> > > > > R-help at stat.math.ethz.ch mailing list
> > > > > https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> > > > > PLEASE do read the posting guide! 
> > > > http://www.R-project.org/posting-guide.html
> > > > > 
> > > > 
> > > > 
> > > > -- 
> > > > Frank E 
> > > > Harrell Jr   Professor and Chair           School of Medicine
> > > >                       Department of Biostatistics   
> > > > Vanderbilt University
> > 
> > ______________________________________________
> > R-help at stat.math.ethz.ch mailing list
> > https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide!
> > http://www.R-project.org/posting-guide.html
> 
> Petr Pikal
> petr.pikal at precheza.cz
> 
> 
> 
>