R help - Jan 2010 - Double inequality with plotmath

Hello,

I'm fairly new to R and I can't work out how to produce a double
inequality like (LaTeX) $0 \leq x \leq 1$ in the legend of a graph. If
I try
> legend(50, 0.1, legend = c(expression(0 <= x <= 1), c(2 <= x <=
3)), pch = c(1,1), col = c(2, 3))
then I get an error message "unexpected '<=' in ...".
I've checked the
help files for plotmath and expression, but could not find a solution.

I would appreciate any help you can give.

Thanks,
Mark

On 21/01/2010 3:50 PM, Mark Seeto wrote:
> Hello,
>
> I'm fairly new to R and I can't work out how to produce a double
> inequality like (LaTeX) $0 \leq x \leq 1$ in the legend of a graph. If
> I try
>
> > legend(50, 0.1, legend = c(expression(0 <= x <= 1), c(2 <= x
<= 3)), pch = c(1,1), col = c(2, 3))
>
> then I get an error message "unexpected '<=' in ...".
I've checked the
> help files for plotmath and expression, but could not find a solution.
>   
That's not legal R syntax, so you have to cheat.  For example,

legend(50, 0.1, legend = expression(paste(0 <= x) <= 1, paste(2 <= x)
<=
3), pch = c(1,1), col = c(2, 3))

Duncan Murdoch