Using $ accessor in GAM formula
Gene, David has given you the preferred code. I just want to point out that the $-accessor is often not the best thing to use. Both dat[["y"]] and dat[, "y"] will work just fine. Peter Ehlers
On 2011-05-05 12:06, David Winsemius wrote:
On May 5, 2011, at 1:08 PM, Gene Leynes wrote:
This is not mission critical, but it's bothering me. I'm getting inconsistent results when I use the $ accessor in the gam formula *In window #1:*
library(mgcv) dat=data.frame(x=1:100,y=sin(1:100/50)+rnorm(100,0,.05)) str(dat) gam(dat$y~s(dat$x))
Error in eval(expr, envir, enclos) : object 'x' not found
I get the same error, but using the standard R approach to passing data and formulae to regression functions I have not difficulty:
> gam(y~s(x), data=dat)
Family: gaussian Link function: identity Formula: y ~ s(x) Estimated degrees of freedom: 4.1552 total = 5.155229 GCV score: 0.002242771
*In window #2:*
gm = gam(dat$cf~s(dat$s)) gm
Family: gaussian Link function: identity Formula: dat$cf ~ s(dat$s) Estimated degrees of freedom: 8.7757 total = 9.77568980091 GCV score: 302.551417213 Has anyone else seen the same thing? In both cases I'm using Windows 7 and R 2.13.0 [[alternative HTML version deleted]]
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David Winsemius, MD West Hartford, CT
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.