First: Thanks to everyone who develops R, maintains r-help, and participates in the list :)
This is a silly follow up question. >From Andy Liaw: > dat <- data.frame(y=rnorm(10), x1=rnorm(10), x2=rnorm(10)) (Silly question - if the answer is on the lm or formula help page I didn't get it:) Why does lm | formula treat dat[,1] slightly differently than dat$y? I see what it is doing - I am curious as to why:) > lm(dat$y ~ .,data = dat) Call: lm(formula = dat$y ~ ., data = dat) Coefficients: (Intercept) x1 x2 -0.08754 -0.04456 -0.16905 > lm(dat[,1] ~ .,data = dat) Call: lm(formula = dat[, 1] ~ ., data = dat) Coefficients: (Intercept) y x1 x2 -5.266e-17 1.000e+00 4.121e-17 -3.274e-17 As Gabor Grothendieck pointed out: lm(formula = dat[, 1] ~ ., data = dat[,-1]) works like lm(formula = dat$y ~ ., data = dat) Curious Minds Want to Know Bob -----Original Message----- From: Gabor Grothendieck [mailto:[EMAIL PROTECTED] Sent: Wednesday, March 24, 2004 12:51 PM To: [EMAIL PROTECTED] Subject: Re: [R] First Variable in lm Christian Hoffmann <christian.hoffmann <at> wsl.ch> writes: > > Hi all, > > I just cannot think of how to do it: > I want to take the first variable (column) of a data frame and regress > it against all other variables. > > bla <- function (dat) { > reg <- lm(whateverthefirstofthevariablenamesis ~., data=dat) > return(reg) > } Andy has already given a particularly concise solution but if your variable is not in first position then you could rearrange the order of the variables to allow his solution or use this which works for any specified position of the dependent variable: data(longley) lm( longley[,7] ~. , data = longley[,-7] ) ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
