[R] math expressions

Uwe Ligges ligges at statistik.uni-dortmund.de
Fri Jan 19 20:03:17 CET 2001

Don Wingate wrote:
> Hello R Users,
> I am trying to use math expressions as the labels to dotplot. I have a
> vector of string values, for example:
> names<-c(x1^2, x2^2)

This won't work:

  names <- c(x1^2, x2^2)
Error: Object "x1" not found

1. You can set "x1^2" in quotes, to make this assignment work.
2. It is a bad idea to call the vector "names", because it's already a

What you could better do is:

  my.names <- expression(x[1]^2, x[2]^2)
  dotplot(1:2, labels = my.names)

> I am trying to do something like this:
> dotplot(c(1,2), labels=expression(names))
> I had hoped that expression(names) would return a vector of math expressions
> which could be used as the labels. It doesn't. Is there any way to do this??

Uwe Ligges
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