[R] help on retrieving output from by( ) for regression

[Marc Schwartz (via MN)]

That works also (using the example in ?lmList)

library(lme4)

?lmList

fm1 <- lmList(breaks ~ wool | tension, warpbreaks)


However, one still would need to use either sapply() or lapply() as
below to get the details that Krishna is looking for. 

'fm1' above is a list of models (S4 class 'lmList') not overly different
from 'tmp' below, which is a list of models (S3 class 'by').

If you review str(fm1) and str(tmp), you would note that they are
virtually identical, save the use of slots, etc.

HTH,

Marc Schwartz

On Thu, 2005-08-25 at 12:17 -0400, Randy Johnson wrote:
> What about using lmList from the lme4 package?
> 
> Randy
> 
> 
> On 8/25/05 9:44 AM, "Marc Schwartz" <MSchwartz at mn.rr.com> wrote:
> 
> > Also, looking at the last example in ?by would be helpful:
> > 
> > attach(warpbreaks)
> > tmp <- by(warpbreaks, tension, function(x) lm(breaks ~ wool, data = x))
> > 
> > # To get coefficients:
> > sapply(tmp, coef)
> > 
> > # To get residuals:
> > sapply(tmp, resid)
> > 
> > # To get the model matrix:
> > sapply(tmp, model.matrix)
> > 
> > 
> > 
> > To get the summary() output, I suspect that using:
> > 
> >   lapply(tmp, summary)
> > 
> > would yield more familiar output as compared to using:
> > 
> >   sapply(tmp, summary)
> > 
> > The output from the latter might require a bit more "navigation" through
> > the resultant matrix, depending upon how the output is to be ultimately
> > used.
> > 
> > HTH,
> > 
> > Marc Schwartz
> > 
> > 
> > 
> > On Thu, 2005-08-25 at 14:57 +0200, TEMPL Matthias wrote:
> >> Look more carefully at
> >> ?lm 
> >> at the See Also section ...
> >> 
> >> X <- rnorm(30)
> >> Y <- rnorm(30)
> >> lm(Y~X)
> >> summary(lm(Y~X))
> >> 
> >> Best,
> >> Matthias
> >> 
> >> 
> >>> Hi all 
> >>> 
> >>> I used a function
> >>>> qtrregr <- by(AB, AB$qtr, function(AB) lm(AB$X~AB$Y))
> >>> 
> >>> objective is to run a regression on quartery subsets in the
> >>> data set AB, having variables X and Y, grouped by variable qtr.
> >>> 
> >>> Now i retrieved the output using qtrregr, however it only
> >>> showed the coefficients (intercept and B) with out
> >>> significant levels and residuals for each qtr. Can some on
> >>> help me on how can retrieve the detailed regression output.
> >>> 
> >>> rgds
> >>> 
> >>> snvk
> >>> 
> > 
> > ______________________________________________
> > R-help at stat.math.ethz.ch mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
> > 
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Randy Johnson
> Laboratory of Genomic Diversity
> NCI-Frederick
> Bldg 560, Rm 11-85
> Frederick, MD 21702
> (301)846-1304
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
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