R help - Jan 2012 - Looping and actual variable names

Dear R users,

I'm a new user to R and have a data set consisting of a number of variables
(in a data frame). I wish to carry out a regression analysis of the first
variable against all the rest in turn. I have used the following code to do this

dd<-read.table("for loop.txt",header=T)
for (j in 2:5) print(summary(lm(formula = dd[,1] ~ dd[,j])))

However, although it produces all the analyses that I want, the output is
annotated with dd[,1] and dd[,j] rather than the actual variable names. Is there
any way around this?

Best wishes,
Alan.

Gordon, Alan wrote on 01/24/2012 09:15:31 AM:
> Dear R users,
> 
> I'm a new user to R and have a data set consisting of a number of 
> variables (in a data frame). I wish to carry out a regression 
> analysis of the first variable against all the rest in turn. I have 
> used the following code to do this
> 
> dd<-read.table("for loop.txt",header=T)
> for (j in 2:5) print(summary(lm(formula = dd[,1] ~ dd[,j])))
> 
> However, although it produces all the analyses that I want, the 
> output is annotated with dd[,1] and dd[,j] rather than the actual 
> variable names. Is there any way around this?
> 
> Best wishes,
> Alan.


Try this:

for (j in 2:5) {
        model <- paste("lm(formula =", names(dd[1]), "~",
names(dd[j]), ",
data = dd)")
        print(summary(eval(parse(text=model))))
        }

Jean
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