refering to variable names in lm where the variable name is in another variable
Have a look at "nam[com[1,1]]" , You're regressing against a character. Try mod<-lm(y~dat[, com[1,1]],data=dat)
--- Daniel O'Shea <dan.oshea at dnr.state.mn.us> wrote:
I am trying to refer to a variable name in a lm regression where the variable name is in another variable, but it does seem to work. Here is an example: y<-rnorm(10)
dat<-data.frame(x1=rnorm(10),x2=rnorm(10),x3=rnorm(10))
nam<-c('x1','x2','x3')
library(gtools)
com<-combinations(3,2,1:3)
mod<-lm(y~nam[com[1,1]],data=dat)
#error in model frame....:variable lengths differ().
I also get the error if i just refer to variable x1
as nam[1] in the lm. any suggestions. I am trying
to set up a for loop that will perform an all
subsets regression and calculate the AIC for each.
Dan
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