Re: List of Frames

[Pete Meyer <pmeyer160@comcast.net>]

Although you can make lists of lists, since frames are

large it probably makes more sense to have a list of

frame names from which to select.  When repeating

an analysis for each of a large number of data frames

with the same content, I list the names of the frames

and abstract the characteristic of interest each time

the analysis is repeated.  In the

following example, assume I am interested in the

coefficient vector when fitting the same model to a

number of datasets.

 

I am using an example from the "lm" documentation

page.

 

#Setup the model with an existing dataframe

mod.1 <- lm(Fuel ~ . , data = "">

 

#Check to see that the function you want

#works with the original data

coef(update(mod.1,data="">

 

#Setup some sample frames (random samples

#of 50 out of 60 rows in the original frame.

frm1 <- fuel.frame[sample(1:60,50),]

frm2 <- fuel.frame[sample(1:60,50),]

frm3 <- fuel.frame[sample(1:60,50),]

 

#Setup up the list of names

list.frameNames <- c('frm1','frm2','frm3')

 

#Use sapply to repeat the model for each dataframe.

betas <- sapply(list.frameNames, function(x,mod.1)

    coef(update(mod.1, data="" mod.1=mod.1)

 

#Assign names to the rows and columns

dimnames(betas) <- list(names(coef(update(mod.1,data="">

    list.frameNames)

 

The point is to use "data="" as a

means of accessing the appropriate data frame when you

need it.

 

Hope this helps.

 

Pete

 

----- Original Message -----

From: "Myers, Brent" <MyersDB@missouri.edu>

To: <s-news@lists.biostat.wustl.edu>

Sent: Monday, April 28, 2003 1:01 PM

Subject: [S] List of Frames

Good day to you,

Is it possible to put frames in a list?

D. Brent Myers
Research Specialist - Agronomy
University of Missouri
158 Ag Engineering Building
Columbia, MO 65211



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