Feng Chen wrote:
Hi,
I have a question about the usage of eval(). Wonder if any experienced user can help me out of it.
I use eval() in the following function: semireg.pwl <- function(coef.s=rnorm(1),coef.a=rnorm(1),knots.pos=knots.x,knots.ini.val=knots.val){ knotn <- length(knots.pos) def.par.env <- sys.frame(1) print(def.par.env) print(environment(coef.s)) tg <- eval( (parse(text= paste( "function(coef.sex=coef.s,coef.age=coef.a,", paste("knot.val.",1:knotn,"=knots.ini.val[",1:knotn,"]",sep="",collapse=","), ")", "{\n print(sys.frame());print(coef.sex)\n y <- c(", paste("knot.val.",1:knotn,sep="",collapse=","), ")\n", " -loglikelihood(coef.sex,coef.age,knots.pos,y)\n}", sep="",collapse="" ) ) ) ,envir=def.par.env)
Why do you want to use eval(parse(.....))? That's not sensible in this case. You can either alculate the stuff doirectly or define a function instead....
Uwe Ligges
print(tg()) print(coef.s) print(sys.frame(1)) mle(tg) }
But when I ran semireg.pwl(), I got correct value for tg(), but an message "Error in eval(expr, envir, enclos) : Object "coef.s" not found" for mle(tg). I just don't know how to make the environment variable visible for mle().
Thanks a lot!
Feng [[alternative HTML version deleted]]
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