I am trying to write a function to do Lasso regression on my data: mylasso<-function(data,k){ gcvs<-rep(0,k) for (i in 1:k){ temp.lasso<-gl1ce(as.formula(paste("y ~ ",paste(colnames(data)[-1],collapse='+'))), data=data.frame(data),family=binomial(),bound=i/k) gcvs[k]<-gcv(temp.lasso)[2] } return(gcvs) } as I execute my function with some data, I get these messages: Warning messages: 1: `x' and `y' have different environments; x's is used in: merge.formula(formula, sweep.out) ... But as I execute commands within this simple function line by line, no warnings are produced. I suspect the data argument should be treated specially but don't know how to. Can anybody give me a solution or hint? Thanks a lot, Mike [[alternative HTML version deleted]]