Re: [R] attach and detach question

From: Chuck Cleland <>
Date: Sat 08 Jul 2006 - 04:15:31 EST wrote:
> I have a large R program that I am constantly running over and over again. At the beginning of this program, I create a hige matrix and a huge dataframe but these are constant. What I mean by constant is that, if I run the program over later, I really should just use the old matrix and dataframe ( if they exist ) that were created in a previous run so that the program doesn't have to spend time creating them. Unfortunately, I don't know how to do this so things take foreeer because every time i do a new run, i recreate these objects and the boss is getting a little annoyed. I know/think that I should use attach and detach commands but
> 1) i can't find an example somewhere of
> just saving two objects rather than the whole session.
> i've looked and looked and i can't find it.
> 2) if i am able to save these two objects, i was hoping that it
> would be possible to write code inside my R program
> that basically says, "if these objects already exist in
> such and such database, then skip over this section of the code
> that creates them".

   You probably want save() and load() rather than attach() and detach().

# Save only a couple of objects
save(huge.mat, huge.df, file="myfile.Rdata")

# Load objects only if they do not exist if(!exists("huge.mat") & !exists ("huge.df")) load("myfile.Rdata") else

   {cat("\n", "Object(s) Already Exist", "\n")}


> if someone has some code or a page number or reference, this is fine because i used to do pretty much this in Splus so think i can figure it out if i can just find an example. thanks a lot.
> ______________________________________________
> mailing list
> PLEASE do read the posting guide!

Chuck Cleland, Ph.D.
NDRI, Inc.
71 West 23rd Street, 8th floor
New York, NY 10010
tel: (212) 845-4495 (Tu, Th)
tel: (732) 512-0171 (M, W, F)
fax: (917) 438-0894

______________________________________________ mailing list
PLEASE do read the posting guide!
Received on Sat Jul 08 04:20:44 2006

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.1.8, at Sat 08 Jul 2006 - 06:15:57 EST.

Mailing list information is available at Please read the posting guide before posting to the list.