I think there is trouble because expr in curve(expr) may be the name of a function, and it's ambiguous whether 'x' should be interpreted as a mathematical expression involving x, or the name of a function. Here are some examples that work:
curve(I(x)) curve(1*x) On Sun, 2011-06-05 at 12:07 -0500, Abhilash Balakrishnan wrote: > Dear Sirs, > > I am a new user of the R package. When I try to use the curve function it > confuses me. > > > curve(x^2) > Works fine. > > > curve(x) > Makes a complaint I don't understand. Why is x^2 valid and x is not? > > I check the documentation of curve, and it says the first argument must be > an expression containing x. > > > expression(x) > Is an expression containing x. > > > curve(expression(x)) > Makes a different complaint and mentions different lengths of x and y (but I > use no y here). > > I understand that plotting the function y(x) = x is rather silly, but I want > to know what I am doing wrong, for the sake of my understanding of how R > works. > > Thank you for support. > Abhilash B. > > [[alternative HTML version deleted]] > > ______________________________________________ > 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.
