persistence of model in R to a file

-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
project.org] On Behalf Of Sharma, Dhruv
Sent: Monday, September 29, 2008 1:52 PM
To: r-help at r-project.org
Subject: [R] persistence of model in R to a file

 Hi,
    Is there a way to save R models (glm, lm , rpart etc) in a file
that
be read in later?

    I noticed models take up space. by space them off and removing them
from memory it seems that would be useful.

    Also why do the models keep a copy of all columns in the original
data set even those columns are not in the model.
    E.g. if I build a model on columns A, B even thought column C
exists
in the dataframe when I run the model against test data with only
columns A and B then I get an error saying column C is missing from the
data.

    Anyway it seems like the models would be more compact without
having
to include within them data from the original data set used to build
them but that is an aside.

    If models can be persisted and loaded selectively later that would
neat.


thanks
Dhruv

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