On Tue, 2011-06-07 at 16:17 +0200, Uwe Ligges wrote: > > On 07.06.2011 11:57, peter dalgaard wrote: > > > > On Jun 6, 2011, at 11:22 , Prof Brian Ripley wrote: > > > >> As a further example of the trickiness, the "function" method of plot() > >> relies on curve(x, ...) being a request to plot the function x(x) against > >> x. I've added a comment to that effect to the help page. > > > > Ouch. This springs to mind: > > > >> fortune(106) > > > > If the answer is parse() you should usually rethink the question. > > -- Thomas Lumley > > R-help (February 2005) > > > > > > but curve() predates that insight by half a decade or more. It could > > probably do with a redesign, if anyone is up to it. > > > > By the way, it really does work if the 2nd arg is an expression object (as > > opposed to an expression evaluating to an expression object): > > > > do.call(curve,list(expression(x))) > > > > or > > > > cl<- quote(curve(x)) > > cl[[2]]<- expression(x) > > eval(cl) > > > > (The trouble with nonstandard evaluation is that it doesn't follow standard > > evaluation rules...) > > If this is not already a fortune, I will add it.
And one more for Uwe's principle: "when discontent, circumvent!" :) > Which is why I useually circvumvent curve(). It is typically faster to > just evaluate a function at positions x and plot it rather than thinking > minutes about how curve() expects its arguments. > > Uwe > > ______________________________________________ > R-help@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. ______________________________________________ R-help@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.
