Thanks Bill and Simon. I wrote a simpler function to test and found out it was stepAIC which causes error, and I still don't know how to solve it. Check out this simple function:
myfun<-function(k){ xx<-mvrnorm(100,rep(0,10),diag(1,10),empirical=TRUE) colnames(xx)<-paste("x",1:10,sep='') py<-exp(sum(xx))/(1+exp(sum(xx))) for (i in 1:k){ y<-rbinom(100,1,py) mydata<-data.frame(cbind(y,xx)) y.glm<-glm(y~.,binomial,mydata) cat("ok here.\n") y.step<-stepAIC(y.glm,direction='both',trace=0) cat("ok here.\n") print(summary(y.step)) } } myfun(10) only one "ok here" is printed. Mike On 8/22/06, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > > Mike Wolfgang asks: > > > > > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Mike Wolfgang > > Sent: Wednesday, 23 August 2006 1:31 PM > > To: R-help list > > Subject: [R] glm inside one self-defined function > > > > Hi list, > > > > I've searched in R-help and found some related discussions but still > could > > not understand this type of error. My own function is pretty complex, > so I > > would not put it here, but the basic algorithm is like this: > > myfun<-function(k){ > > mydata<-...#by someway I create a data frame > > mymodel<-glm(y~.,family=binomial(),data=mydata) > > ...#some other stuff > > } > > I think you are leaving out something. Here is a test of what you > claim gives a problem (R 2.3.1, Windows): > > > myfun <- function(n) { > + z <- rnorm(n) > + mydata <- data.frame(x = z, > + y = rbinom(n, size = 1, prob = exp(z)/(1+exp(z)))) > + fm <- glm(y ~ x, binomial, mydata) > + fm > + } > > > > myfun(100) > > Call: glm(formula = y ~ x, family = binomial, data = mydata) > > Coefficients: > (Intercept) x > 0.1587 1.0223 > > Degrees of Freedom: 99 Total (i.e. Null); 98 Residual > Null Deviance: 137.6 > Residual Deviance: 118.3 AIC: 122.3 > > Not even a murmur of complaint. (This also works in S-PLUS 7.0 but > earlier versions of S-PLUS gave a problem rather like the one you note, > curiously.) > > Look again at your code and see if the abstract version you give > really matches what you did, may I suggest? > > > > > as I execute this function, it gives error like this > > Error in inherits(x, "data.frame") : object "mydata" not found > > > > So I guess glm here tries to find "mydata" in the parent environment. > Why > > doesn't it take "mydata" inside the function? How to let glm correctly > > locate it? Is this (scope/environment) mentioned in R manual? Thanks, > > > > Mike > [[alternative HTML version deleted]] ______________________________________________ R-help@stat.math.ethz.ch 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.