[R] model.frame.default problem in function definition

[Darryl Greig]

Could someone point me in the right direction for the following issue:

A function is defined as follows:

	tfun <- function(dat)
	  {
	    fmla <- as.formula("y~x+z")
	    dat2 <- dat
	    mdl <- lm(fmla,dat2)
	    mdl <- step(mdl)
	  }

Then the following code

	dat <- data.frame(x=1:10,z=1:10,y=(1:10)^2+10*(1:10))
	tfun(dat)

generates the output

	Start:  AIC= 43.67
	 y ~ x + z

	Error in model.frame.default(formula = y ~ z, data = dat2,
drop.unused.levels = TRUE) :
		Object "dat2" not found

Any help or pointers gratefully accepted.

Thanks,
Darryl Greig (darryl at hpli.hpl.hp.com)