[R] percentage sign in expression

[e-letter]

On 24/08/2010, David Winsemius <dwinsemius at comcast.net> wrote:
>
> On Aug 24, 2010, at 9:37 AM, e-letter wrote:
>
>> Readers,
>>
>> According to the documentation for the function 'plotmath' there is no
>> apparent possibility to add the percent sign (%) to a plot function,
>
> Where did you see an assertion made???
>
Within R I entered the command:

?plotmath

Also accessed using:

help.start(browser="opera")

Navigating the web browser page:

packages
packages in /usr/lib/R/library
grdevices
plotmath

In the list headed 'syntax' and 'meaning' within the section 'details'.

>> e.g.
>>
>> plot(a[,1]~b[,2],ylab=expression(x~%),xlab=expression(z))
>
>
>>
>> How to achieve this please?
>
> Read the plotmath helo page more carefully. The section immediatedly
> below the plotmath expressions points you to the use of the symbol()
> expression-function and to the points help page where generation of
> the available glyphs proceeds according to the advice on help(plotmath):
>
In my system the paragraph immediately after the list of features
(i.e. 'syntax','meaning') describes a note to TeX users. I cannot see
reference to 'symbol()'.

>  > TestChars <- function(sign=1, font=1, ...)
> + {
> +    if(font == 5) { sign <- 1; r <- c(32:126, 160:254)
> +    } else if (l10n_info()$MBCS) r <- 32:126 else r <- 32:255
> +    if (sign == -1) r <- c(32:126, 160:255)
> +    par(pty="s")
> +    plot(c(-1,16), c(-1,16), type="n", xlab="", ylab="",
> +         xaxs="i", yaxs="i")
> +    grid(17, 17, lty=1)
> +    for(i in r) try(points(i%%16, i%/%16, pch=sign*i, font=font,...))
> + }
>  > TestChars(font=5)
>
> Notice that the "%" sign is three characters to the right (i.e.
> higher) of the "forall" symbol that is produced by the example code

I can't see 'forall' in the code above.

> they offer. (The numbering proceeds from bottom up which confused me
> at first.)
>
What numbering?

The documentation makes reference to the command:

demo(plotmath)

I applied this command and could not see an instruction to produce the
percent (%) symbol.