R help - Feb 2009 - beginner's question: group of regressors by name vector?

dear r-experts: there is probably a very easy way to do it, but it eludes  
me right now. I have a large data frame with, say, 26 columns named
"a"
through "z". I would like to define "sets of regressors"
from this data
frame. something like

myregressors=c("b", "j", "x")
lm( l ~ myregressors, data=... )

is the best way to create new data frames that contain all the variables I  
want, then use ".", and then destroy them again? or am I overlooking  
something obvious?

sincerely,

/iaw

	[[alternative HTML version deleted]]

If DF is a data frame with the variables, try this:

lm(l ~. , DF[c("l", "b", "j", "x"))


On Thu, Feb 12, 2009 at 11:11 AM,  <ivowel at gmail.com>
wrote:
> dear r-experts: there is probably a very easy way to do it, but it eludes
> me right now. I have a large data frame with, say, 26 columns named
"a"
> through "z". I would like to define "sets of
regressors" from this data
> frame. something like
>
> myregressors=c("b", "j", "x")
> lm( l ~ myregressors, data=... )
>
> is the best way to create new data frames that contain all the variables I
> want, then use ".", and then destroy them again? or am I
overlooking
> something obvious?
>
> sincerely,
>
> /iaw
>
>        [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

The predictors and outcomes in lm can be matrices, so you could use something
like the following:
 
x.mat=cbind(x1=rnorm(20),x2=rnorm(20))
y.mat=cbind(y1=rnorm(20),y2=rnorm(20))
lm(y.mat~x.mat)

David Freedman

ivowel wrote:
> 
> dear r-experts: there is probably a very easy way to do it, but it eludes  
> me right now. I have a large data frame with, say, 26 columns named
"a"
> through "z". I would like to define "sets of
regressors" from this data
> frame. something like
> 
> myregressors=c("b", "j", "x")
> lm( l ~ myregressors, data=... )
> 
> is the best way to create new data frames that contain all the variables I
> want, then use ".", and then destroy them again? or am I
overlooking
> something obvious?
> 
> sincerely,
> 
> /iaw
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> 
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